# Convert NG to LP 1950's stove



## eclecticcottage

I think I may have found my new stove..maybe.  It's a 1950's era Bengal, but it's set for NG like pretty much EVERY stove I find!  How do we convert this to LP?  I know it involves orifice size and a regulator, but that doesn't really mean a lot to me.  This isn't a super popular brand like magic chef or tappan, so trying to find info on line so far hasn't gotten me much info specific to it.  I did try emailing a propane company a week or so ago about switching to thier service and if they would convert an older stove and never heard back (big surprise).

I was going to go with an early 20's/30's stove, but I REALLY like the 50's era stoves and this one would match one of the retro new fridges they make like they weer made for each other:


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## DAKSY

Some of these older unit were designated for one type of fuel & non-convertible.
Check to see if there's a rating plate on the back or inside one of the compartments. 
That plate may contain the info on the conversion requirements. Otherwise, you may
have to take it to a licensed repair shop to see if it can be done.


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## eclecticcottage

Hm.  Good to know.  I'll have to ask.  Do you know if the older ones (20/30's) were the same?  I figured this would be a project, but I didn't think it would be quite this frustrating!  When we bought the Old House, I wanted a vintage stove but we didn't want to put that much weight on the spot where the stove would logically go.  So, no old stove.  When we bought the Cottage, it was A-#1 on my list, since I've spent 12 or so years wanting one (ok, really, a lot longer since the only reason I wanted a Holly Hobby oven when I was a kid-ONLY Holly Hobby, NOT an Easy Bake-was the fact that it was made to look like an old wood cook stove).  I found a Chambers in a color I LOVE, but it's several states away.  Of course THAT one is converted to LP.  Everything I find locally, even out in the country, is NG it seems.  I tried contacting a stove repair shop somewhat nearby and they don't "work on 1900's stoves" so I was hoping to find a way to do this ourselves.  I'd love an old wood cook stove with the gas option, but I think those all have wood ovens (then again, I don't know how often I'd use the oven in the summer).  Plus I'm not so sure our insurance company would love that idea!  Also I don't know that I could find one in good, working condition that wouldn't cost a fortune either...and I'm not so sure how we'd move it, much less get it into the Cottage, lol.


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## eclecticcottage

Just for reference, http://www.antiquegasstoves.com/pages/parts/gas.html has a valve about mid page for @ $50 that is supposed to convert from NG to LP with no orifice changes.  I'll have to see if they think it will work with the Bengel.  30" vintage ranges are not easy to find.


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## eclecticcottage

Just another update in case anyone is interested.  The company did get back to me on the valve, but they didn't state if it would specifically work for the Bengal, just that it was as I figured, to be used to convert from NG to LP or LP to NG without any other changes, including orifice changes.  We're going to look at the Bengal tomorrow and hopefully haul it home.  The seller believes it has a way to be converted in the supply line, so I am thinking it has a reversable valve already (I had looked at a different stove that did, but it was too big to fit in our kitchen).  That seller stated the stove came with it, and you just had to flip the regulator and adjust the orifices.  I can't believe I might have my vintage stove finally.  Now if we could just find some faux brick linoleum (we actually already have faux brick lino, but it's not in very good shape after all these years)....lol.


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## 49er

Congratulations on your new stove, I sure hope it works out for you. We have one of the Heartland reproduction stoves and it has the reversible regulator to go from NG to LP also. There are a few other adjustments that need to be made though, the oven control valve has a small screw that needs to be turned from one gas to the other for the pilot light. We also had to turn the orifices for the oven and stovetop burners to the proper position but these adjustments were all built into the stove. You might want to verify that these kind of things are already built into the stove you are looking at. 
Good luck and keep us posted.


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## eclecticcottage

Just picked up the Bengal (it's made by Floyd Wells) for $60.  Two hour drive each way.  Will be checking into converting to LP, it looks like it's doable, pretty easy to switch out the burners, etc.  Needs a good cleaning, two of the burner grates need to be repaired, but overall it's on good shape.  No bells or whistles, just a basic stove (unlike some of the Okeefe and Merritts, etc with Grillavators, peroscopes, etc)-not even an oven light.  But I am happy with that-nothing to go wrong, rewire, etc and it won't use any electric!  We won't have it in for a while, we've got to repair the floor in the kitchen so we'll take our time and get it all pretty.


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## celticsam

If you get information on how to convert that old Bengal, let me know.  I picked up one (model unknown...no plate) that needs to be converted.


(hopefully that is a picture of the stove...)

Neil


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## celticsam

OK, so here's what I am looking at doing.  Having seen the cost of adding a standing pilot system, and not (so far) being able to find what size orifice tubes to use, I am looking at getting a free gas stove (people give them away all the time on Craigslist), and scavenging the entire gas system from it to retrofit onto my beautiful Bengal.  The top burners from the Bengal along with the pilot already on top will be retained, but the burner, pilot and gas lines to the oven and broiler will be swapped, along with any necessary valving, ect (thermostat, safety valve, ect...)  Seems to me to be mostly a matter of time rather than money, and, barring gas leaks, which are easily checked for (gas detecter and soapy water), should be as safe as the stove that donates the parts.  Any thoughts or better ideas?


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## eclecticcottage

Celticsam, nice stove!  My tag was inside the door on the left side.  I've seen that style stove previously when searching for Bengal stoves, although I think yours might be a little newer than the ones I usually find (50's era vs 40's).  They were built in PA so I think they are a more regional stove (like the Detroit Jewel) vs a Magic Chef or O'Keefe and Merritt.

We aren't sure about the valve yet, I am working on trying to find replacement burner grates and we have to tear out the floor in the kitchen to do some repairs so I haven't really gotten very far yet on converting it.


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## eclecticcottage

Ok, this whole thing is peeving me off.  the "valve" they sell (referenced above) is nothing more than a pressure regulator, from what I was able to pry out of the company.  I can tell you I wouldn't deal with them after trying to get more info on one little part, that's for sure. 

So I'm left with a question...if this so called professional resto company is selling a simple pressure regulator and stating it will eliminate orifice changes...do you actually have to change the orifices, or just regulate the incoming pressure??  Somehow this doesn't seem right, since I imagine EVERY appliance connected to gas (either propane or NG) has a regulator that brings the WC to the correct amount inline before it.  Right?

The set up on the Bengal (at least for the cook top, haven't investigated the oven) is pretty simple.  There's a central pilot with four tubes that aren't sealed to it (open ended) running from that pilot to the burners (again, open on the end).  Is it possible that we don't need to change anything to use this with propane, just be sure the WC is @ 10-11?


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## DAKSY

I don't think you wanna run 10 - 11" of Water Column thru a natural gas burner orifice.
For the pilot, you will probably get a "candling" effect where the pilot will come
thru the orifice & then turn upwards. As long as it still engages the thermocouple,
it should work fine. But if you've never seen a Natural Gas burner operating with
Liquefied Petroleum pressures, I'd make sure you stand back from the stovetop
when you turn it on. The flames are gonna be huge in comparison, because of the
larger orifice size & the larger burner ports. I've only encountered that combination once,
in an NG gas fireplace that was installed in a LP environment & when I fired it up, it scared
the HELL outta me. BIG flames.
YMMV, but I doubt it.
***Others may chime in at this time***


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## eclecticcottage

That's what I thought, which is why I couldn't figure out what this valve was supposed to be doing.  Mr Eclectic called them today and got the same run around with no answer as I did, so I have zero trust in them or the product.  Too bad we can't seem to find anyone locally that will give any info/pats/work on this "old" of a stove!

Here is what we have for a set up-is the small white object in the center of pic # 3 the orifice?  This is in the center of pic # 2, where the pilot is and the tubes that feed the burners run from.  Would we be able to remove an orifice from our old stove, a vintage (1970s?  1980s?) hotpoint to use that?  It has an electric pilotless ignition however (if pics would help I can get them).


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## eclecticcottage

Hm.. Ok, these are pic #3 and #4


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## eclecticcottage

Oh, and yes, parts are loose.  I know how they go back together, things got jostled around moving it from the PO's house, into our truck, out of the truck, into our house.  Also, I need to clean in there still.


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## coaly

Natural Gas is used at HALF the pressure (approx. 1/4 psi compared to 1/2 psi with LP) with about TWICE the size oriface as propane. It's due to the specific gravity of the two gasses.
There are tables to figure out the oriface size per BTU required at each burner.

Natural Gas pressure is regulated lower (about 1/2 the pressure of LP) at the regulator in the gas valve. When converting to Propane, the regulator is blocked open to allow the *system supply regulator* to supply the required 10" Water Column pressure. Convertible valves have a cap that sets the spring pressure correct for Nat, and flipped over puts more pressure on the spring, actually blocking it open. Valves made for either gas ONLY are not convertible, meaning you can't change the pressure in the regulator. That's the only difference.

Here is a gas oriface sizing chart. http://www.joppaglass.com/burner/lowp_chrt.html
It requires numbered oriface drills, but it gives the diameter in thousandths as well. I have a set of numbered oriface drills, so never had to measure the one needed with a micrometer, but that's how you can make sure you use the correct size if you don't know the size of the drill bits you have.
Orifaces are normally brass, and can be peened shut with a ball peen hammer (closed) and redrilled from Nat to LP. You will also find them soldered shut and redrilled. The oriface stays cold at the air intake, so this works too. It's nice to have a threaded piece of steel that the oriface screws into used as an ANVIL to protect the threads if you peen it shut. That's why many used solder.

The air adjustment will need to be set on each burner as well to obtain an all blue flame. Yellow tips are a no no and will cause carbon deposits on pans. It's quite simple once you do it. New ranges have adjustible orifaces that come set for Nat. and you simply turn them down tight to close the hole to the LP setting. Some older appliances that were convertible had a set of orifaces screwed to the back to change to the gas being used.

I'm retired from my own LP gas service business and this is what I did, as well as installing systems. There are now laws requiring a lable to be affixed on the appliance and signed by the installer. This identifies which gas the appliance is set up for.


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## coaly

When sizing the pilot oriface from Nat to LP, you will find you need an extremely small hole for LP. (The pilot hole for Nat is almost the main burner hole size for Propane)  Normally the correct size oriface is used, since it will be only a few thousandths. Pilot holes are cleaned with a pilot broach. It looks like a needle with fluted sides about the thickness of a human hair. They can be tapered, so the farther they are run in, the larger the hole. You may be able to peen them shut partially until you get it small enough, then true up the hole with a broach. The size of the hole is like holding it up to the light and seeing a speck of light. A dirty or irregular hole will appear fuzzy, like you need glasses. A clean round proper hole will be a speck of light. Some pilot orifaces are made by stamping with a certain letter to allow the proper amount of gas through. Changing the letter changes the oriface size. This is an art that is probably gone with high button shoes.
  Pilot broaches are so small they are sold in a vial by the dozen. They are easy to break, and can be used in a pin vise spun by hand like most oriface drills.


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## eclecticcottage

thanks coaly, you just confirmed exactly what I thought.  The reason I am suspicious of the valve I was referring to was this line on their site "Installing this part eliminates the need to change all of the orficies".  I can't figure how that could be possible.

If the orifice is usually brass, then I am guessing that what I thought was the orifice is not (which is actually in the middle of pic #4, because for soem reason they uploaded opposite of how I was trying to load them)...so...since I have never found another other reference to this model stove ANYWHERE and am pretty unlikely to find any diagrams or manuals-where should I be looking to find it?  Is there any reason I can't or shouldn't scavange a "new" one from my old stove (we will be scrapping it, the oven doesn't work properly and it's pretty beat up and ugly-but it came with the Cottage).

Am I correct in assuming (yeah, I know, assuming is BAD) that the "flaps" in pic #3 that are open a certain amount are the air controls for the burners?


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## coaly

From the supply line the gas comes through the "manifold" to the stove top burner valves or oven control valve. The last thing it goes through is the oriface. Gas vapor actually pushes out the air in the "Mixing Tube" (The long tube between the air intake and oriface and burner). This is called a mixing tube since the gas mixes with oxygen in it and needs about 70 buckets of air to one bucket of gas. Atmospheric pressure pushes into the air shutter or air adjustment hole into the mixing tube and is ignited at the burner. The entire burner should stay relatively cool since the flame is actually above the burner. Incorrect fuel pressure or incorrect air adjustment can cause the flame to jump inside the mixing tube and burn at the oriface like a torch in the tube. This overheats the tube and burner and must be avoided. You will know if it does by a fluttering and roar sound in the burner.
  When you size the oriface for the BTU you want from each burner, It's best to open the air shutter about half way. Closing it will give you yellow flame tips. Open it until yellow is gone, and that should be about right. Too much air will lift the flame off the burner. (Too small of an oriface for a burner can make the flame circle around the burner and chase itself or go out).  The reason for air adjustments is altitude (air density and pressure) as well as slight variations in regulator adjustment. (pressure through the oriface)

No idea why they would say you don't need to change an oriface with valve replacement. That would be true for a stove top burner valve with the oriface attached to the valve, with adjustable oriface like new ranges. Otherwise the pressure regulator in a valve controls the pressure at the oriface, and oriface size controls the volume of gas going through it.

If you want one burner hotter than the others, (on any range) you can always drill it out slightly more than the others and run the air wide open. As long as there are no yellow tips, you will be getting more BTU from that burner. As soon as you go too big, even with air wide open, you will still be rich and have yellow flames, so you need ro resize it down to obtain an all blue flame. When you find the largest oriface you can use and have blue flame with air wide open, that would be the max BTU for the burner.


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## coaly

By your pictures, it looks like "cottage53" is looking at the top of the pilot oriface.

The mixing tubes connected to burners have the air adjustment at the main oriface for each burner in the manifold. The burner tube (mixing tube) sets over the oriface where the gas comes out of the manifold. You can see the oriface looking through the air intake shutter. There is such as thing as *oriface alignment*; so the oriface "shoots" the gas up the center of the tube creating a good mix, but that's pretty much a part of the design of the burner tube. Centering the burner tube on the oriface is all you can do. In water heaters, where the mixing tube can be installed crooked over the oriface, you can imagine how the gas would go in crooked and mix incorrectly with turbulence in the mixing tube. Probably more than you need to know.


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## eclecticcottage

Thank you! Now we just have to find orifices...and clean the heck out of it!

Here it is in place anyway


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## eclecticcottage

Question...could we have adjustable orifices? If I'm understanding everything correctly, that's what these appear to be?

The first photo shows the needle inside of the outer brass piece which may be screwed on and off, you can see the one for the other burner on that side still on in the top part of photo two.


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## coaly

No idea what year they started adjustable orifaces. That point looks like the needle on a newer stove with an adjustable oriface. As you turn the oriface down to the pointed tip, if it looks like it's coming through the hole in the "cap" that is what makes the hole smaller. Normally turned down snug leaves a little opening around the tip that allows the correct amount of LP gas out for the burner.
A dab of grease or anti-sieze on the valve threads where the cap screws down helps give you the "feel" when the thread bottoms and the oriface cap is snug where it should be. If there is anything on the threads, and it binds, you may think it's bottomed out, but the oriface is still partially open. When you screw them down, compare how much of the point sticks out of each one, to get an idea if they are turning down fully. Some get pretty tight, and you don't want to twist a burner valve off. I wouldn't say there's a trick to it, but some are worse than others. Some new ones feel like they're cross threaded they turn so hard. Perhaps they put locktite on them now to hold the Nat. position from the factory. I've had a few turn extremely hard.

If it has adjustable orifaces, it should have a settable regulator as well. Usually in-line at the connection, the cap may say NAT on it, and when you unscrew the cap and flip it over, it was have an LP on it. This cap presses on the spring in the regulator. Natural Gas position allows the spring to go up inside the cap, decreasing pressure on the spring. LP position will be designed with a shoulder or stud on the cap that increases pressure on the spring. (increased pressure pushes the diaphram open to bypass this appliance regulator. This allows full system pressure to appliance from the main regulator at tank. If you Google "appliance regulator" you'll probably find info and pictures of different regulators. Your original question was geared towards regulators built into safety valves. (found on water heaters, furnaces .....)Is there an appliance regulator at the gas connection on this stove? That is where the regulator normally is on kitchen ranges. The supply line goes into the regulator first.

If there is a pilot adjustment on the pilot line before the pilot oriface, you may be able to turn it down, and use the same pilot oriface. This adjustment screw in the lin ecan also be used to shut th epilot completely off. Not all ranges have them, most older ones do.


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## eclecticcottage

Awesome...

As far as a regulator goes, I think someone disconnected the line after it, I've never seen an appliance with a hook up starting inside of it like this one (pic to follow). We do have a propane regulator in the supply line that we disconnected from the old stove.

Is the adjustment screw for the pilot the one in the second pic?

THANK YOU for helping with this Every place I've contacted locally pretty much runs when I mention the age of the stove. The way it's built with no bells or whistles, once we get it going we should have it forever, unlike the one we had at our old house that SUCKS. Now to find a matching fridge :D


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## coaly

You're OK with the correct pressure from system regulator. There is no regulator on your stove to cut it down for Nat. You will already have 10" W.C. at the stove connection to burner oriface from your system regulator.

As long as the line shown with the adjustment screw is the pilot line, yes that's the pilot adjustment. It may branch off and supply the oven pilot as well. Not all older stoves have a oven pilot. Some are match lit every time, and when the oven comes up to the temp set on thermostat, there is a bypass in the thermostat that when it closes the main flow to oven burner, it bypasses enough around the Tstat valve to reduce to a very small flame on main burner. This is better than a pilot since the small flame maintains temperature better than shutting down completely. But this is usually on commercial stoves.

Another use for that scew is doing a leak down pressure test. First you shut off the pilots with it, and remove one stove top burner. Normally a manometer is put on the oriface from removed burner. (rubber hose fits over oriface end with burner removed) Gas is turned off at the tank, and burner valve connected to meter is opened. This shows system operating pressure. By relieving pressure at another top burner, when meter starts to drop, the bleed burner is closed, and the meter must hold the test pressure for 10 minutes. This leak tests the entire system including all fittings on stove without soaping everything.  

There's no reason for appliance service companies to shy away from old stoves other than parts availability. (and not being familiar with them, since they probably learned on newer appliances) The basics are still there for combustion and flame control. I prefer the older ones since they have more adjustments on them, and no electric is required.

Yours may have a simmer burner as well. You will know by removing the knob. If there's a small screw on the end of the shaft under the knob, that is the adjustment for setting the gas flow on low. With it lit, you hold the shaft from tuning on low. Running the screw in will decrease the flame down to little dots. A true simmer is blue flames that do not go above the rim of the burner looking across it - eye level with the burner top. When a stove is in a drafty location, many times the simmer adjustment is raised to keep it from blowing out. Most people don't know there is a low adjustment on good ranges. Many new ranges will have one designated simmer burner with this adjustment screw under the knob.

Imagine the looks I'd get if I asked questions at a gas or appliance place about the equipment I work on !  Antique chicken brooder heaters, amonia refrigeration powered by gas or kerosene, and propane toilets !! (they are stainless toilets that you clamp the lid shut, fire on propane and dump the ash from a tray)  I've built some LP Gas burners to heat locomotive wheels to change tires too. A loop the size of the wheel that uses 10 psi. This was common knowlege years ago.

The oven burner is going to have the same type adjustable oriface that admits the gas into the burner tube. Since they run hotter than the stove top burners, they can be stuck and need PB Blaster or WD-40 to loosen first, then grease the threads and turn down snug for the adjusting pin to close that oriface as well. (very little grease on the threads only so it doesn't plug the oriface hole) Again, no yellow flames or flame tips. All blue by setting air adjustment. If you can't get the yellow out, the cap s probably feeling tight on the threads and not closed fully on the pin. Usually a 1/2 inch wrench cautiously turned a little at a time until just snug. It's easy to overtighten with a big wrench. Don't use a big adjustable. Small open end wrench only on oriface caps. Valves and caps are soft brass.


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## coaly

The threaded connection looks like it has thread tape or sealant on it ?
   Brush it clean with a wire brush. No sealant is used on a flare since the angled end is the mechanical joint. The threads are straight, not tapered and only pull it tight. The threads are not used for sealing like on tapered pipe threads that require sealant. Tape on a straight flare or hose thread only binds the threads so you can't feel it tighten properly on the seat.


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## eclecticcottage

WIn   We do have to adjust three of the burners, they are a bit excessive.


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## eclecticcottage

Still have to adjust the oven and broiler, we haven't touched that yet.  Also...this one seems to put off more heat than the old Hotpoint.  WOWZERS.  And the burners aren't adjustable (like low, med, high) so there will be a learning curve there.

But it's in.

THANK YOU THANK YOU THANK YOU


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## coaly

They are hot burners. There's no yellow, so they are fine. Notice the light blue flame down at the burner, then it becomes a darker blue secondary flame that mixes with others and becomes one. This is like adjusting a torch when you have a pencil tip light blue flame that becomes the larger secondary flame. When you set a water filled kettle on the burner, you'll notice the flame change. At the highest setting, you want the flames to come to the edge of the kettle or pan, not up the sides. That's wasted heat. My commercial Garland star shaped burners are 30,000 each. I'd guess yours to be 15 to 20,000 each? Maybe more.
There's no way to tell without knowing the oriface hole size.

Check above the pilot for soot in a day or so. Then periodically. If you see an accumulation of black soot, it's too big. People tend to adjust pilots too large. It doesn't take much. Depending on the cup the pilot sits in, the rule of thumb is to the top of the cup looking across the top of it. If the cup is low, the pilot flame should only be as high as the center of the pilot tube. (the tube gas goes from burner to pilot through to light burner)

Let me know if you have problems with the oven. It should adjust the same way.


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## eclecticcottage

We did adjust the other burners a little. Two are perfect, one is pretty good and one is ehhh. It will take a little tweeking, but that's fine. The flames were wrapping up around the edges of our bigger pot on three if them, so we figured we should see if we could get them a bit smaller. After looking "under the hood" of the hotpoint I can't see why someone wouldn't want to work on this vintage of a stove-it's so much more straigh forward! Oh well.

Is the oven orifice down in the oven? I haven't really looked for it yet, but I know It didn't look like it was up under the burner cover with the others.

Oh and just for good measure since I kept posting pics before I cleaned under there...this is what it looked like after cleaning (without the burners or crumb trays in)


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## coaly

Yes, it's in the oven. The burner tube will be one piece like the top burners. Gas is admitted at the air intake / adjustment area, fuel mixes with air in the tube before coming out the holes. Sometimes the burner tube sits over the oriface and you need to remove the burner to tighten down the oriface. Others are far enough from the oriface to tighten it down wihtout removing the burner.

*Here's a few IMPORTANT things before you start trying to light the oven;*
I don't know the type of oven control this uses to ignite the main burner and be controlled by the thermostat without close ups of the thermostat control valve and pilot / burner.

**** Open the top, and look carefully at the thermostat control for a little screw shank that sticks out with a cross piece like a T handle. (Or a T handle with only one side of the "T" like a motorcycle or small engine fuel shut off valve. It will have Nat and LP stamped on it, so you need to turn this adjuster over to the correct fuel. This changes the size of the oriface in the control valve so the "pilot control" is the correct size. ****

This could be the screw shown on picture #60. Somewhere on the control valve should be the adjuster that can be set to either N or P for Nat or Propane , or Nat and LP.

This thermostat is a "pilot control" and is what keeps the pilot small to maintain a fire when oven is off or not calling for heat. When the T-stat is turned on calling for heat, the small pilot becomes much larger. That is what controlls the oven burner in this type of control. This larger pilot flame heats the oven safety valve capilary tube. The fluid in this tube expands and opens the oven main burner valve. (called a "safety valve") It takes time when the T-stat calls for heat and the pilot increases in size to heat the safety valve. 30 seconds to a minute for the oven valve to open. Make sure both the Nat / LP "switch" on the control and oriface is correct for LP before lighting. It takes time for the capilary tube on the safety valve to cool down to shut the main burner off as well.

LP Gas vapor on a stove top is bad enough, but confined inside an oven can become much worse. Leave the door open until you're sure the burner is correct, lights smoothly, and burns blue.


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## eclecticcottage

I know it's a robertshaw (or so says the oven temp control knob), but that's about it.  It's a match light oven, no standing pilot there.  I will take a look tonight and post if we have any questions.


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## coaly

OK, that type without a standing pilot will hand light the main burner, and when it comes up to temp, the main burner shuts off and a bypass in the T-stat allows the main burner to go down to a very small flame. Almost little dots at each hole in the burner to just stay lit.
  That's the first type themostatic control of the oven. Then came standing pilot with safety valve, (like I explained in previous post) then electric spark, (DSI or Direct Spark Ignition) and now glow bars to warm the safety valve and ignite the oven.


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## eclecticcottage

Win x2! This was pretty easy actually. DH went over to a friends house to see if he had a spring for the carb on a little cultivator we picked up so I tackled it. The access for the orifice and the air flap are in the storage area next to the oven. The only thing with tuning the gas/air mix was waiting for the dirt to burn through after each tweak (yellow flames).  And realizing I could check he flame via the broiler instead of leaving the "floor" out of the oven, lol.

THANK YOU again!  And we now have an oven for the first time here.  YAY.  Now we need to get an oven thermo and see if it's calibrated correctly.


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## coaly

Yep, it's easy once you do it. The next one you look at may seem completely different, but the basics are still there.

You're right, the yellow is from dust and dirt knocked loose in the burner tube or can even be contaminents in the air (dust from shirt sleeves) that burns as it goes through.

Some oven thermostat knobs have a screw on the back that the center portion that goes over the valve can rotate and slide in a slot, so you hold the knob center still and turn the knob to put the degrees on the face where you want them. Some ovens with broiler door under them are supposed to be used with broiler door partially open for proper circulation. That changes the temp. too.

Glad I could walk you through it.


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## eclecticcottage

Just popping back in to say we're still running the Bengal without issue. We use both the burners and oven regularly and it seems to use very little propane. I even found it a friend:






that is a 1950's Norge Customatic, snagged it for $100.  Runs super, quieter than our 200? Kenmore AND uses less electric than the (energy star rated) Kenmore too.

Check out the egg keeper thingy:






I couldn't stop there of couse, so I picked this up for $25:






that is a 1960's era Kitchenaid 4C.  Works great, just needed a serious cleaning.


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## sunmtnforge

coaly said:


> Natural Gas is used at HALF the pressure (approx. 1/4 psi compared to 1/2 psi with LP) with about TWICE the size oriface as propane. It's due to the specific gravity of the two gasses.
> There are tables to figure out the oriface size per BTU required at each burner.
> 
> Natural Gas pressure is regulated lower (about 1/2 the pressure of LP) at the regulator in the gas valve. When converting to Propane, the regulator is blocked open to allow the *system supply regulator* to supply the required 10" Water Column pressure. Convertible valves have a cap that sets the spring pressure correct for Nat, and flipped over puts more pressure on the spring, actually blocking it open. Valves made for either gas ONLY are not convertible, meaning you can't change the pressure in the regulator. That's the only difference.
> 
> Here is a gas oriface sizing chart. http://www.joppaglass.com/burner/lowp_chrt.html
> It requires numbered oriface drills, but it gives the diameter in thousandths as well. I have a set of numbered oriface drills, so never had to measure the one needed with a micrometer, but that's how you can make sure you use the correct size if you don't know the size of the drill bits you have.
> Orifaces are normally brass, and can be peened shut with a ball peen hammer (closed) and redrilled from Nat to LP. You will also find them soldered shut and redrilled. The oriface stays cold at the air intake, so this works too. It's nice to have a threaded piece of steel that the oriface screws into used as an ANVIL to protect the threads if you peen it shut. That's why many used solder.
> 
> The air adjustment will need to be set on each burner as well to obtain an all blue flame. Yellow tips are a no no and will cause carbon deposits on pans. It's quite simple once you do it. New ranges have adjustible orifaces that come set for Nat. and you simply turn them down tight to close the hole to the LP setting. Some older appliances that were convertible had a set of orifaces screwed to the back to change to the gas being used.
> 
> I'm retired from my own LP gas service business and this is what I did, as well as installing systems. There are now laws requiring a lable to be affixed on the appliance and signed by the installer. This identifies which gas the appliance is set up for.


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## sunmtnforge

Hello-I have a late 40's Wedgewood stove set up for natural gas.  I am running LP and will solder and redrill the orifices.  Mine has 2 orifices per burner, one goes to a center ring the size of a dime, the other feeds the main burner (3 1/2" dia in the back and 4" dia for the front burners).  I was planning on drilling around a #65 to start with but after reading your info it sounds like I might need a variety of hole sizes and would rather start small and bring them up to needed BTU's rather than resolder again after overdrilling.
Also-I do not know what to do for the pilots as they appear to be tubing(sealed) with no apparent removeable orifice.
ANY advice would be deeply appreciated Coaly


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## coaly

Pilot line normally has what looks like a cap over the end of line where it attaches to pilot burner with smaller than a pin hole in the end. If you remove the line from pilot burner it may stick inside the burner and need to be pulled out of the pilot burner. Sometimes a wooden match pressed into the "cap" shaped like a tiny sewing thimble wedges into the oriface and you can pull it out. (1/8" lines) !/4" lines have a larger oriface (not hole size) that matches the line diameter. Normally a compression fitting that the ferule seals against the flared out end of the oriface.  A pilot burner has a way to get oxygen to mix with the fuel just like a main burner. So the size of that oriface isn't as critical as a main burner. Normally simply adjust the flow on the pilot line. You should be able to follow the pilot line back to an adjustment screw that will adjust the pilot flame height as well as shut it off. (for pressure testing) If the end of the line looks like it is pinched shut to make the oriface, you may be able to shut the pilot off, and holding a match to the pilot slowly turn it on until it lights. If the pilot line connects to thermostat for oven pilot as well, there should be a screw to turn with arrow or pin pointing to Nat or LP that changes the pilot line flow with an internal oriface inside thermostat. You only want a small candle flame to prevent soot accumulation above pilot. If it has pilot tubes directing gas from burner back to pilot, the pilot flame should be no higher than the top of the tube height.
If there is a tag on the range giving BTU of burners, I can give you the oriface sizes to achieve the proper BTU at your 10" W.C. operating pressure.


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## sunmtnforge

coaly said:


> Pilot line normally has what looks like a cap over the end of line where it attaches to pilot burner with smaller than a pin hole in the end. If you remove the line from pilot burner it may stick inside the burner and need to be pulled out of the pilot burner. Sometimes a wooden match pressed into the "cap" shaped like a tiny sewing thimble wedges into the oriface and you can pull it out. (1/8" lines) !/4" lines have a larger oriface (not hole size) that matches the line diameter. Normally a compression fitting that the ferule seals against the flared out end of the oriface.  A pilot burner has a way to get oxygen to mix with the fuel just like a main burner. So the size of that oriface isn't as critical as a main burner. Normally simply adjust the flow on the pilot line. You should be able to follow the pilot line back to an adjustment screw that will adjust the pilot flame height as well as shut it off. (for pressure testing) If the end of the line looks like it is pinched shut to make the oriface, you may be able to shut the pilot off, and holding a match to the pilot slowly turn it on until it lights. If the pilot line connects to thermostat for oven pilot as well, there should be a screw to turn with arrow or pin pointing to Nat or LP that changes the pilot line flow with an internal oriface inside thermostat. You only want a small candle flame to prevent soot accumulation above pilot. If it has pilot tubes directing gas from burner back to pilot, the pilot flame should be no higher than the top of the tube height.
> If there is a tag on the range giving BTU of burners, I can give you the oriface sizes to achieve the proper BTU at your 10" W.C. operating pressure.





coaly said:


> Pilot line normally has what looks like a cap over the end of line where it attaches to pilot burner with smaller than a pin hole in the end. If you remove the line from pilot burner it may stick inside the burner and need to be pulled out of the pilot burner. Sometimes a wooden match pressed into the "cap" shaped like a tiny sewing thimble wedges into the oriface and you can pull it out. (1/8" lines) !/4" lines have a larger oriface (not hole size) that matches the line diameter. Normally a compression fitting that the ferule seals against the flared out end of the oriface.  A pilot burner has a way to get oxygen to mix with the fuel just like a main burner. So the size of that oriface isn't as critical as a main burner. Normally simply adjust the flow on the pilot line. You should be able to follow the pilot line back to an adjustment screw that will adjust the pilot flame height as well as shut it off. (for pressure testing) If the end of the line looks like it is pinched shut to make the oriface, you may be able to shut the pilot off, and holding a match to the pilot slowly turn it on until it lights. If the pilot line connects to thermostat for oven pilot as well, there should be a screw to turn with arrow or pin pointing to Nat or LP that changes the pilot line flow with an internal oriface inside thermostat. You only want a small candle flame to prevent soot accumulation above pilot. If it has pilot tubes directing gas from burner back to pilot, the pilot flame should be no higher than the top of the tube height.
> If there is a tag on the range giving BTU of burners, I can give you the oriface sizes to achieve the proper BTU at your 10" W.C. operating pressure.


Coaly-The only tag I am seeing is to the right of the magnetic valve.  It says Wedgewood and the model or serial number.  The writing is worn off but below that are numbers that were luckily stamped into the metal tag: 24000  9000  18000 not in a row but vertically.  Because the (painted?) tag is worn I can't see what it said to explain the numbers.  Do these pictures help?


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## coaly

Pilots are all adjustable with the small screw on the line where they connect to manifold and T-stat. So you shouldn't have to touch those orifices.
Can't tell if the top burner orifices are adjustable. It looks like the top burner orifices are adjustable by the threads showing where the orifices are screwed onto the valves. Remove burner from orifice and remove 1 brass orifice (cap) on burner valve. If there is a little needle sticking out of the valve that goes into the orifice hole, simply turn them down until snug so the needle protrudes more. This is the LP setting. Oven would be the same.
If no needle you will have to change orifice size.
I would imagine the oven is 24000 (#53 drill size)
The top burners would be the two smaller orifices unless one burner is smaller on stove top for a simmer burner being the 9000.
1800 is #55 drill size and 9000 is #64. These drill sizes are for an *open orifice without needle* that closes the opening to an adjustable size.

The top plug on thermostat is a test port, and you should WD-40 the capillary line where it is green with corrosion behind t-stat. Carefully polish it with a rough rag or Scotch Brite with the WD to clean. It's just from dissimilar metals where soldered, but keep it clean.

1). The appliance regulator will probably have a reversable cap you flip over for LP. Most are stamped on each side, so it may be stamped NAT now and when you unscrew the cap it will be stamped LP inside so LP is viable when you put it back on. This increases the spring pressure to open appliance regulator fully so the appliance gets full line pressure from low pressure regulator.

2). Set LP/Nat screw on thermostat to correct position. (possibly behind knob on this thermostat)

3). Verify orifice sizes.

After regulator pressure is set and orifice sizes are correct;
Close the pilot adjusters for the top burners AND close the pilot adjuster fully for the oven before turning on gas.
Turn on gas and pressure test. Should hold pressure at 10" WC for 10 min. This shows no leaks in system as well as entire appliance.
Light pilots by opening each pilot adjuster screw slowly with match held to pilot and adjust pilot burners to correct height.


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## sunmtnforge

Coaly-There are 2 orifices per burner on this range.  Both front burners are larger than the back burners.  The one that feeds the large outer circle has a larger hole and what appears to be a 3 sided  (disperser?) inside the tubing, I don't think that is the needle you are referring to.  The one that feeds the small interior circle just threads onto open tubing and has a smaller hole.  Here are more pictures- I am not sure where you are referring to "the top plug on the thermostat" is my screwdriver pointing to it?  Is the screwdriver pointing to the screw I should tighten for the pilot?  Broiler on the left and oven on the right side.  I have an appliance regulator on the line in to the range I am replacing but I do not see one on this range.  I am thinking maybe I have a lot of itsy bitsy different sized holes I have to break off bits in. Oh yeah and that center orifice is for the griddle (probably around the size of the broiler and oven orifices?)


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## coaly

Yes that is the pilot adjustment and test port.

The part of the burner that goes from orifice to burner is the mixing tube where air and fuel are mixed. Anything inside it creates turbulence for a better air/fuel mix. Newer ranges have an open tube and will not have that good quality of a blue flame as your burners.
The needle would be inside the orifice cap, that is a part of the burner valve pointing into the orifice hole. You need to unscrew the orifice from valve to see it, or look into the orifice hole to see the tip. If it is there, when you turn the orifice down tight on the valve it will stick out of the orifice hole a little so the gas has to come around it. That closes the large size for NAT down to LP.
The BTU totals are total of both burners combined into one. I didn't know you had a griddle, so those BTU numbers are probably rear burners lowest, front burners middle and griddle the highest. It won't matter if you have adjustable orifices. BTU is only needed if you have to make the orifice the correct size yourself.

*** Nothing in your pictures is showing any antiquity that a current gas company shouldn't be able to convert. Are you sure it's not from the late 50's? Have you been operating it on Natural Gas? It doesn't appear to be as old as your claim having a thermocouple operated safety valve. Oven pilot size is critical to heat the thermocouple correctly. The threads under orifice in oven looks like the orifice can be simply turned down the same as a modern appliance. (adjustable orifice)
If you are supplying your own fuel to an antique appliance I can help, (you assume all liability) but if this is connected to a supply from a gas supplier check with them for liability and what type certification they require to convert appliances.***

An appliance regulator is only mounted to the appliance where it is connected to supply line. Any other regulator is a system regulator. It can be single or dual stage, both are designed to supply the correct pressure to appliance. With LP, the system regulator is the only pressure control since the appliance regulator is blocked open by the higher spring pressure. Converted to the Natural position, the appliance regulator keeps a constant low pressure to range if the supply pressure raises for any reason.


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## sunmtnforge

coaly said:


> Yes that is the pilot adjustment and test port.
> 
> The part of the burner that goes from orifice to burner is the mixing tube where air and fuel are mixed. Anything inside it creates turbulence for a better air/fuel mix. Newer ranges have an open tube and will not have that good quality of a blue flame as your burners.
> The needle would be inside the orifice cap, that is a part of the burner valve pointing into the orifice hole. You need to unscrew the orifice from valve to see it, or look into the orifice hole to see the tip. If it is there, when you turn the orifice down tight on the valve it will stick out of the orifice hole a little so the gas has to come around it. That closes the large size for NAT down to LP.
> The BTU totals are total of both burners combined into one. I didn't know you had a griddle, so those BTU numbers are probably rear burners lowest, front burners middle and griddle the highest. It won't matter if you have adjustable orifices. BTU is only needed if you have to make the orifice the correct size yourself.
> 
> *** Nothing in your pictures is showing any antiquity that a current gas company shouldn't be able to convert. Are you sure it's not from the late 50's? Have you been operating it on Natural Gas? It doesn't appear to be as old as your claim having a thermocouple operated safety valve. Oven pilot size is critical to heat the thermocouple correctly. The threads under orifice in oven looks like the orifice can be simply turned down the same as a modern appliance. (adjustable orifice)
> If you are supplying your own fuel to an antique appliance I can help, (you assume all liability) but if this is connected to a supply from a gas supplier check with them for liability and what type certification they require to convert appliances.***
> 
> An appliance regulator is only mounted to the appliance where it is connected to supply line. Any other regulator is a system regulator. It can be single or dual stage, both are designed to supply the correct pressure to appliance. With LP, the system regulator is the only pressure control since the appliance regulator is blocked open by the higher spring pressure. Converted to the Natural position, the appliance regulator keeps a constant low pressure to range if the supply pressure raises for any reason.
> 
> In my #1 above in post #41, it should read; In LP mode "this INCREASES the spring pressure to open appliance regulator fully so the appliance gets full line pressure from low pressure regulator".


     Coaly-I was told by the seller that he thought this was a 1948, I don't know.  I do not have adjustable orifices.  I am confident that I can solder and redrill these if they are not readily available at reasonable cost.  I will purchase the necessary bits but I prefer to get the hole sizes correct the first time.  Yes I am supplying my own propane to this for a Mother-In-Law and it is the only gas appliance.
Are the 2 units with the red ends (Robert Shaw) system regulators?  They only affect the broiler and the oven.  The pilots that heat the thermocouples for the oven and the broiler are both adjustable.  Did you see the last thumbnail picture above showing where the orifices were removed?  I am assuming the oven and broiler orifices are the same but I have not taken it off yet.


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## sunmtnforge

sunmtnforge said:


> Coaly-I was told by the seller that he thought this was a 1948, I don't know.  I do not have adjustable orifices.  I am confident that I can solder and redrill these if they are not readily available at reasonable cost.  I will purchase the necessary bits but I prefer to get the hole sizes correct the first time.  Yes I am supplying my own propane to this for a Mother-In-Law and it is the only gas appliance.
> Are the 2 units with the red ends (Robert Shaw) system regulators?  They only affect the broiler and the oven.  The pilots that heat the thermocouples for the oven and the broiler are both adjustable.  Did you see the last thumbnail picture above showing where the orifices were removed?  I am assuming the oven and broiler orifices are the same but I have not taken it off yet.


P.S.- on the 2 orifices/burner that I took off, currently the smaller one is now sized to pass a # 76, the larger is plus # 61 (largest pin bit I have)


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## coaly

Got it.
Here is a chart that shows Nat. and LP orifice sizes as well as drill diameter in thousandths. Don't worry about the BTU not exactly what you want. The chart is for 11" WC and you may have 10" or a little less during flow, so round up.
http://andersonforrester.com/conversion-chart/

The system regulator is at the LP cylinder valve. This reduces vapor pressure in tank to 10 to 11" W.C. (approx. 1/2 psi)
The appliance regulator would be what the supply line or flexible connector connects to. I see non in the picture of safety valve showing flex connector.

Are you referring to the safety valve with red button being a regulator? That's why I asked if you used this range with Natural Gas so I would know if you knew how to light it.

No gas will flow through that valve until the red button is depressed. This manually opens the safety valve allowing gas to flow to oven pilot. (you can see the oven pilot adjustment screw that controls flow through the safety valve to pilot next to t-stat) Adjust pilot flame down before lighting since it is likely adjusted high for Nat. now. Hold match at oven pilot while depressing red button and the pilot should light when the gas gets down to it. Adjust pilot flame while holding button in. The pilot flame heats the upper third of the thermocouple causing dissimilar metals inside the thermocouple to touch. This creates a very low electric current flow up the thin wire to the safety valve. This current flow goes through a coil in the safety valve making an electromaget inside the valve that holds the valve open when you let go. So you have to hold the button 30 seconds to a minute after pilot lights to hold the safety on when you let the button out. If it goes out right away, you didn't hold long enough, or the pilot flame is not hot enough on the thermocouple (dirty pilot is the the usual case) or the thermocouple or coil in valve itself is bad. (min. 25 mv or 1/4 volt) These systems usually outlast the appliance. The parts themselves are not problematic. Usually gas flow or operator error. The red button also has to seat a steel pin against the electro magnet head inside. Some require a strong push before you let go to seat pin on magnet head. The steel pin has to contact the magnet head inside to hold it on when released.
Us gas men use more electric meters for troubleshooting electric on "gas" systems than gas tools. The reason for the safety valve is if the pilot goes out the thermocouple stops producing voltage to the magnet coil and the gas flow is shut off. If oven thermostat calls for main burner ignition, there is no flow to main burner. With this type pilot, you can't have it burn too weak or too strong. (it will flame cut or melt thermocouple tip)

If you follow line from the square valve with red label I think you'll find it goes to the oven main burner. That would be the oven control valve. (it gets gas flow from t-stat when calling for heat sensed by capilary tube)

Look around for a bracket that may hold the orifices you need.  They normally came with both for different gasses and may be hidden on a clip type holder somewhere ! On back or behind bottom doors ? It wouldn't surprise me if you found them somewhere on the range screwed onto threaded studs to store them.


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## coaly

Some of those valve threads can get corroded so you may want to soak the orifice threads overnight with PB Blaster or penetrant of choice. It's not unheard of to break a valve removing an orifice. You can see how thin the soft brass wall is. Don't force them and work back and forth if necessary as they are removed.


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## sunmtnforge

coaly said:


> Some of those valve threads can get corroded so you may want to soak the orifice threads overnight with PB Blaster or penetrant of choice. It's not unheard of to break a valve removing an orifice. You can see how thin the soft brass wall is. Don't force them and work back and forth if necessary as they are removed.


     Well, I am very sad to say that I have taken all removable parts off and searched everywhere and underwhere to no avail trying to locate more orifices.  The only questionable panel is pictured but does not have an obvious way to remove it, there are 2, on the outside wall that have a keeper at the top and a tab at the bottom.  The ones on the inside wall have a screw, and inside appears to be hinge related (in my case broken springs)-refer to pics.


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## coaly

The way orifices are sized in that case is with a tool that comes with an orifice kit that looks like a small center punch which has a round tip. You put the orifice over a metal rod that fits inside it and use the punch around the hole to close it up. They are made of a malleable material that is easily cold worked. Then drill to size. (normally hand drill with pin vise)
You should be able to get door springs by length. Replace both to keep tension equal.


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## Woodchuckinn

Hello! This thread is amazing. The history, science, and knowledge available here is incredible. @coaly I’m hoping for your expertise to convert a beautiful WellBuilt stove from NAT to Propane.

Here are some pictures to get started. I have only cleaned her up so far...


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## coaly

Can't read the tag. Does it say for Natural only, or is there a box to check for Propane?
Is the BTU for top burners and oven readable on tag?
Do you have a manometer or U-tube gauge?
Remove an orifice for top burner to see if the valve has an open hole for gas to come through, or if there is a tip of a needle sticking out of the valve that will go into the orifice and close the hole as the orifice is turned down the threaded part of valve farther. That would be an adjustable orifice that makes it relatively simple.
If no needle, you will need to size the orifice yourself. I can walk you through that procedure, but if you have no BTU rating on the tag, you will need to measure the orifice you have to calculate the BTU currently for Nat. and keep it the same BTU or close with the LP size. This will take a set of orifice drills to measure the existing Natural orifice size. (Use the chart I linked to on post #46) The cost of a manometer and orifice drill set is far more than having it converted unless you already have those tools.
Lastly, is the appliance connected to an existing LP supply system? Or are you the supplier with your own cylinder and regulator?

There must be a service valve at the other end of appliance connector shown in the first picture. Keep that valve shut off to prevent gas flow into appliance until a manometer or U-tube gauge is connected to leak test entire appliance after converting. This assures the entire appliance has no leaks as well as all pilots and burners have no flow by completing a leak down test. If you're not familiar with leak down testing and equipment, you may be able to size the orifices yourself and have the supplying propane company (if there is one) leak check it for you.

Depending on the supplier, they will probably require a pilot safety valve to be installed. That is the push and hold type safety valve to light pilot. No gas can go through the thermostat to oven burner without the standing pilot being lit.

Any supplier should require an oven safety valve that can only open when pilot is lit, or pilot heat activates main burner. This prevents gas flow into oven burner without a proper pilot to ignite the oven burner.


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## Woodchuckinn

Thank you @coaly! I should have included more details in the original post. 

The tag was in bad condition, so unfortunately it doesn’t help much. The tag has a spot that says what the stove is setup for. It is stamped NAT.

The stove was connected to natural gas in the city and was working fine, I assume without leaks, until it was disconnected. All I’ve done is clean it up. I wasn’t really worried about leaks because it was being used regularly.

I don’t have any of the special tools you mention. Also, I don’t have a propane provider. I just have a gas line that is attached to a small Blue Rhino type tank. This was working fine with the previous newer Home Depot type stove that was here when we moved in. I can go see what that attachment looks like. I guess there is a regulator there.

The great news is that the orifices do have a needle sticking out so I plan to tighten them down to close the produce size.

I should just tighten them all the way?

Is there anything else I need to adjust?

Thank you for all the help!


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## Woodchuckinn

I’ve tightened one orifice, to see how the needle/cone will sit inside the hole. There are more threads left, but I didn’t want to over tighten them. It looks like (from what I can see) that it completely blocks the hole... is that right?

Here is a close up of the two orifices, the right one having been tightened down.

Also, here is a picture of the tank and regulator setup.


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## coaly

I assume that cylinder is NOT indoors, it must be outside, never inside any building.
The regulator on the cylinder is not a 2 stage regulator which is required on any automatic operated appliance. (oven) The type you have is called a Bar-B-Que regulator which is only for manually operated appliances such as an outdoor grille with no thermostat. You need a 2 stage regulator by code.

Not sure why there is a service valve on supply line near cylinder. It is not required. That type valve needs to be at the supply line where flex connector connects to supply line.

Just tighten orifice until snug, don't over tighten. It should be metered through the needle. You can test it for flow by removing valve and blowing through valve with it "on".
Same as oven burner as long as it is the same type.
That takes care of sizing the orifices for Propane.
Next is pressure and pilots.

Close all pilot adjustment screws until snug, again do not over-tighten.
I can't see the pilot adjustment for oven in your pictures. It should be on the thermostat housing where pilot line comes out of T-stat., but some are an inline tiny valve with screw shut off / adjuster.

With pilots lines connected and burners installed on top, this completes the range top burners.

The oven burner is more complicated. You have not posted any pictures showing a safety valve of any type on the appliance. I suggest a propane service person or propane company install a safety valve that _*prevents the oven thermostat from passing gas through the oven burner orifice when there is no flame present at pilot burner.*_ It is beyond the scope of explaining what you need without the full understanding of how a safety valve with electromagnet powered by a thermocouple works, and knowing the exact parts you need without having the appliance in front of me. A picture of a safety valve is shown in post #42 of this thread. (with red button) The original poster was able to do their own conversion since their appliance had the required safety equipment. The problem with yours is _*IF*_ the pilot were to go out when the burner shuts down. (oven up to temp, burner shuts down. There are reasons for a burner to light or shut off abruptly, extinguishing pilot due to lack of oxygen to the pilot burner. Oxygen is actually consumed by the "pop" of abrupt ignition, and now you have an open burner with no pilot flame. A safety valve shuts gas off to thermostat eliminating this very dangerous condition) So as the temperature in oven drops, and thermostat opens, gas flows through oven burner. NO pilot light present allows gas to build up in oven until one of the stove TOP pilots ignites the oven. Since propane is heavier than air, most drops out the bottom until something else in the home ignites the oven. You can imagine you would not want to be in the same building when the oven or entire room lights explosively. That is why all gas appliances now require this safety equipment.

The leak check is not only for leaks from moving an appliance, but also to be sure there is no gas flow coming out of a pilot or burner before lighting anything. The procedure is to put a tee in the line for testing AFTER the service valve so when on, it reads system pressure to the appliance. The service valve should have a test port, but if not, a test Tee is used to tie into the system. With all valves closed and ALL pilot adjustment screws closed, the entire appliance  from service valve to every orifice is being pressure tested. By shutting the service valve off, residual pressure is bled off until gauge starts to drop quickly showing even a very slight pressure drop. It then must hold pressure 10 minutes with no drop. If a pilot were on, pressure would drop off almost immediately showing you don't have a sealed system, so you would not attempt lighting anything on or near the appliance. Once you know there is no gas flow, you turn on the service valve, then holding a match to a pilot, slowly open the pilot adjustment screw. This is the only pilot burner that would light since you know you have no flow anywhere else. Obviously the pressure test leaves no guessing that any gas is coming out anywhere. Without a proper leak down test, you could be working on an upper pilot or burner and go to light the oven which has had gas seeping from a pilot or burner. So obviously there is no danger when you know it held pressure. The gauge doesn't lie, (but you need to know how to use it!) you can't soap every inch of every line, and you wouldn't want to spray soapy water into each pilot to look for bubbles. An open pilot would blow the soap off without bubbling anyway. A pressure leak down test is the only way to safely retire after doing this for 25 years.

There is much more to leak down testing and converting which takes days or weeks of training through propane suppliers such as how to read a gauge drop. As an example, think of pressure on a gauge as how much water is in a bath tub. When letting water out of a full tub, the drop of water is not noticeable. That is how a drop looks on a gauge with a lot of pressure. You can't see it. Now as the water is almost out of the tub, the last gallon or quart looks like it is moving very fast. That is how pressure drop works on a gauge as the pressure gets lower. It is more noticeable, yet the same leak is still there just as the same amount of water was moving out of the tub when full. Just buying a manometer doesn't mean you know how to use it without proper training.


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## Woodchuckinn

Ok, thank you again. I really appreciate the time and advice. I’m going to call the local propane company and have them come out to pressure test and install the safety valve. I’m gonna pick up the two stage regulator myself. This one should be good right?


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## coaly

Yes.
See, when you have single stage regulation, a regulator has to go from cylinder pressure which can be anything from 1 or 2 psi to the relief pressure set at 375 lbs. That is asking a lot to control that much of a pressure difference in one decrease down to 1/2 psi. Having one regulator section that decreases to 10 psi (first stage) means it will be keeping the pressure close to 10 from cylinder pressure of 10 pounds up. As an example, if 100 psi is controlled down to 10, and 200 psi is controlled down to 11 and 300 psi is controlled down to 13, the second stage is capable of regulating 10 to 13 psi down to 1/2 far more accurately than 300 down to 1/2. Pressure in the cylinder varies that much by temperature. So the more stages of regulation, the more accurate it gets. With water, you could have 500 to 400, to 300, to 200...... all the way down to the last set at 35 lbs keeping it very steady no matter the flow.
Regulators also have different size orifices inside where the needle goes into the seat which opens and closes. This size of opening is what determines the BTU capacity of the regulator. Too small of an opening will freeze up, stopping flow if you are allowing too much though a regulator with not enough capacity. So sizing is critical for the BTU max. expected to go through the regulator.


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## kmagill

Hello! Desperate need of assistance and this thread hopefully will provide some answers...  @coaly I’m hoping for your expertise on an old gas stove we picked up to go in a off-the-grid little cabin.  We believe it maybe a 1930's American Stove CO Reliable 3 burner gas stove.  We were told it was set up for propane it had an old regulator that hooked up to an old ID threaded tank and copper pipe that connected the stove, leaked bad everywhere.  We reviewed many articles and note the orifices were never changed because they are too big.  
We don't believe there's pilot light - nor a thermostat, unless we're missing something?

We think we need new orifice's (they aren't adjustable on stove - no pin seen when orifice was removed). 
We measured the orifice size using a drill bit and 1/16" drill bit slide through loosely.   
Following are the questions we have...
1/ Orifices & BTU's - don't know what the BTU's are on the Original orifices but based on conversion table 1/16" = 0.0625 do we simply do math based on 4.0 Natural this would be ~ #68 orifice?  Does that seem right and where do you buy these special size orifices?
2/ Oven orifice - no idea, we removed it and it has an outer 1/4" opening that narrows inside to less than 1/8"...maybe 3/32"? or 7/64" hole, any ideas on what we should replace this with? 
3/ Regulator - without a thermostat, what kind of regulator do we need?  is the propane tank house regulator sufficient?  or do we need a 2 stage regulator?  
4/ hook up to stove - we bought CSST pipe and the 1/2" fitting works, plan to run this through the wall to connect to propane tank hose outside.  Can we simply connect to a standard propane tank flex house with the built in regulator?

/
	

		
			
		

		
	



	

		
			
		

		
	
 Burner                                                           Burner Control Knob w/ orifice 
	

		
			
		

		
	



Orifice close up 
	

		
			
		

		
	



	

		
			
		

		
	
                                                                            Regulator that came w/ stove 
	

		
			
		

		
	





     Oven 
	

		
			
		

		
	



	

		
			
		

		
	
        Oven Orifice


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## dvd545

Hi @coaly 
Wow! what a wealth of information already on this thread. Your quite the expert when it comes to these LP stove conversion proccess. 
I have an old Caloric stove that was run on natural gas. I am trying to convert it to LP however I have come up completely dry with any information regarding converting it. I purchased a propane regulator and hooked it up to a propane tank hoping that I might get lucky but unfortunately it seems the orifices are way too big. The flames were gigantic. It also doesnt appear that the orifices are adjustable. (no pin)

The orifices have a number 30 printed on them. Do you know what that might mean?
How do I size the correct BTU's for these burners? 
Also how would I adjust the flame on the oven portion? Is there a orifice somewhere inside the thermostat control? 

Attached are some pictures of the stove, hopefully that will help.
Looking forward to your reply!
Thanks in advance.


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## o0oo00o0o

Hi. I could use some help from @coaly. I’ve got a Wedgewood that I think is from the 50s. It’s a dual wood/gas setup, and has a gas griddle in addition to four gas burners.




It came to me set up for natural gas, but thanks to the advice you gave @eclecticcottage, I was able to tighten  down the burner and oven orifices for LP.  As for the pilot screws, they seem to just turn and turn, without loosening or tightening no matter which way I turn them. For the burner pilots, I was able to use a wrench to hold a nut on the bottom side of the screw going through the lines and then turn the screw tighter. Have you seen this before, and if so, did I do the right thing? As for the oven pilot, it’s set up differently. It just turns and turns. See my photo below.






My oven also has a safety valve:




There are no NAT/LP labels anywhere—including behind the thermostat knob, which I took off to check—so I also wanted to know if there’s anything else I need to adjust besides the orifices and the pilot screws.

Last question: this is the line that will connect to the LP line that comes in from my tank outside. 




I am serviced by a propane company, and like others have mentioned, they took one look at the Wedgewood and told me they weren’t sure how to convert it, but once I did it myself they’d happily hook it up for me (which is basically telling me they refuse to help, because hooking it up to the line is easiest part!). I’m not sure I have a regulator for my current stove, which is a pretty new Hotpoint (like less then 20 years old). Currently the LP line connects right to the Hotpoint via a flex line. I would need to buy a regulator to connect to the pipe coming from the Wedgewood, correct?

Is there anything else I need to do for the conversion? Thanks!


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## DAKSY

I'd say you're gonna need to change the valve or at least the regulator head. It might be best to pull the valve so you can see if you can find some identification on it.  Maybe then we can research what needs to be done.


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## coaly

Pilot screw (oven in-line) is probably open when the slot is with the pipe, closed when the slot is across the pipe like a quarter turn valve. They will keep rotating and not made to screw open or shut. If you do a pressure test, try turning the screw slot across the direction of flow to see if that stops flow and the appliance holds pressure before lighting. Then crack the pilot adjustment screw to watch for pressure drop showing you have flow.

Sounds correct for burner pilots having a seat type valve to turn closed.

The pressure is regulated by the low pressure regulator or supply regulator at the source. The adjustable regulators added on the appliance cut the pressure down to about 1/4 psi for natural using a spring inside and are actually blocked open in the LP mode to use full system pressure from supply regulator.


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## coaly

If the oven thermostat doesn’t have an adjustment to set for Nat or LP, that should be it as long as the oven main burner orifice is sized correctly for the btu rating of the burner. You can tell by the orifice size that was there if it was sized for Nat. Just use the same btu size orifice for LP to match the original Nat. size output. It should be all blue with only minimal yellow tips when correct.


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## o0oo00o0o

coaly said:


> Pilot screw (oven in-line) is probably open when the slot is with the pipe, closed when the slot is across the pipe like a quarter turn valve. They will keep rotating and not made to screw open or shut. If you do a pressure test, try turning the screw slot across the direction of flow to see if that stops flow and the appliance holds pressure before lighting. Then crack the pilot adjustment screw to watch for pressure drop showing you have flow.
> 
> Sounds correct for burner pilots having a seat type valve to turn closed.
> 
> The pressure is regulated by the low pressure regulator or supply regulator at the source. The adjustable regulators added on the appliance cut the pressure down to about 1/4 psi for natural using a spring inside and are actually blocked open in the LP mode to use full system pressure from supply regulator.


Thanks, @coaly! I was able to get the stovetop working nicely, but I’m having some trouble with the oven. The gas is collecting around the orifice and doesn’t seem to be traveling up and through the broiler tube to meet the pilot light you see in the forefront of the photo. In the picture below, the orifice is behind that silver metal plate in the back. After lighting the pilot and holding the red button on the safety valve, I could smell gas,  but the oven wouldn’t light.  when I took a match to it, the area around the orifice lit up. Do you know what might be preventing the gas from traveling like it should? After the orifice lit up, I turned of the gas and made sure the safety valve clicked on, so no gas is going to the oven orifice until I can get it working. Thanks again for your help!


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## coaly

o0oo00o0o said:


> Thanks, @coaly! I was able to get the stovetop working nicely, but I’m having some trouble with the oven. The gas is collecting around the orifice and doesn’t seem to be traveling up and through the broiler tube to meet the pilot light you see in the forefront of the photo. In the picture below, the orifice is behind that silver metal plate in the back. After lighting the pilot and holding the red button on the safety valve, I could smell gas,  but the oven wouldn’t light.  when I took a match to it, the area around the orifice lit up. Do you know what might be preventing the gas from traveling like it should? After the orifice lit up, I turned of the gas and made sure the safety valve clicked on, so no gas is going to the oven orifice until I can get it working. Thanks again for your help!
> 
> View attachment 287271


The first thing I would suspect is something inside the burner. Spider web, cocoon, rust? The tube that goes from the air intake at oriface to the first burner holes is the air mixing tube. This is where the air fuel mixture mixes before coming out of the burner holes. Something in it will cause this.

Did you remove the burner to clean? A pipe cleaner works well, or any thin wire (like bell wire or thermostat wire) pushed in and twirled around catches spider webs and cocoons to pull them out. Also use a small drill bit by hand to clean each hole in the burner. Knock it around gently by tapping and dump debris out the air intake hole. If you have compressed air, you can blow it out as well.

If it's difficult or impossible to remove burner due to rust of a fastener, the metal plate is the air adjustment. Open it all the way and insert wire up burner, twirl and remove to see if anything is on the wire. Not as good as removing and dumping, but may be enough to clean out a blockage. That's common after they sit for an extended period of time.

When burner lights, adjust air shutter by closing until flames go yellow on th tips. Open until all blue. You will get flicks of yellow and a rough flame until all the dust and rust particles come out and burn off. It will then settle down to all blue.


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## o0oo00o0o

coaly said:


> The first thing I would suspect is something inside the burner. Spider web, cocoon, rust? The tube that goes from the air intake at oriface to the first burner holes is the air mixing tube. This is where the air fuel mixture mixes before coming out of the burner holes. Something in it will cause this.
> 
> Did you remove the burner to clean? A pipe cleaner works well, or any thin wire (like bell wire or thermostat wire) pushed in and twirled around catches spider webs and cocoons to pull them out. Also use a small drill bit by hand to clean each hole in the burner. Knock it around gently by tapping and dump debris out the air intake hole. If you have compressed air, you can blow it out as well.
> 
> If it's difficult or impossible to remove burner due to rust of a fastener, the metal plate is the air adjustment. Open it all the way and insert wire up burner, twirl and remove to see if anything is on the wire. Not as good as removing and dumping, but may be enough to clean out a blockage. That's common after they sit for an extended period of time.
> 
> When burner lights, adjust air shutter by closing until flames go yellow on th tips. Open until all blue. You will get flicks of yellow and a rough flame until all the dust and rust particles come out and burn off. It will then settle down to all blue.


I made sure the burner was clean, but I’m still not getting a flame. The best I got were a few brief flames. I checked both the orifice and the burner by hooking them up together where the griddle is, and they work fine there. But for some reason, down in the oven chamber the gas doesn’t seem to travel through the burner. It merely pools around the orifice. Any ideas?


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## coaly

o0oo00o0o said:


> I made sure the burner was clean, but I’m still not getting a flame. The best I got were a few brief flames. I checked both the orifice and the burner by hooking them up together where the griddle is, and they work fine there. But for some reason, down in the oven chamber the gas doesn’t seem to travel through the burner. It merely pools around the orifice. Any ideas?


Restriction or something preventing correct pressure to orifice . Gas is just drifting out instead of pushing air out of burner tube. If you put a manometer on orifice it will probably be extremely low. Needs 10-11 inches WC at orifice.


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