# Converting a 1930 Humphrey Radiant heater to LP



## Billy62 (Jan 8, 2018)

Hello..has any one converted a gas radiant fireplace heater from Natural gas to LP?...I need to change the orifises to a small diameter...(10).....anybody out there know anything or is it useless..its a beautiful heater and all radiants are intact....any help would be appreciated...thanks!


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## coaly (Jan 9, 2018)

If the appliance regulator is adjustable to LP it's not a problem.
Natural gas operates at about 1/2 the pressure of LP. The regulator could have a reverseable cap you flip over. Something will block the regulator open in LP mode to get full pressure from system low pressure regulator. If there is no adjustment on appliance regulator, remove it.

For oriface sizing refer to oriface drill charts for the BTU required. Larger holes were normally peened shut with a ball point punch then redrilled. Some gas valves have a rotating switch from Nat. to LP that sizes pilot flow through valve. (such as found on oven pilot controls) Others require correct pilot oriface.

Use the far right column for LP at 11 inches W.C here for BTU needed;
http://web.go-spi.com/sinclairdev-n...air-supply/pdf/Gas-Orifice-Capacity-Chart.pdf


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## Billy62 (Jan 9, 2018)

Thanks for the quick response but Im a little fuzzy on some things...1.  is a gas grill tank (20lb) and regulator OK?....attached are pics..2..how do I know if the Humphrey regulator can be "flipped"?....The guy who sold me the ceramics said I probably need 1/64th holes and to peen the existing closed....I can do that, just a little afraid of ruining the heater if I get it wrong...attached are some pics..I will upload nipple pics in an hour....Thanks all!...Billy62


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## coaly (Jan 9, 2018)

First, you can't use galvanized fittings.The 90* elbow looks like silver galvanized in your picture, unless it is stainless. They can be black iron or brass.

The cylinder must be outside the building. Stored outside the building, used outside the building. Never store it or bring it inside ANY building.

Not knowing the BTU of your heater and system there is no way to properly size a cylinder. (Tanks are ASME lay down type - you have a DOT cylinder) If this is the only appliance supplied I'm sure the 20# cylinder is fine. (it goes by wetted surface area of pressure vessel that we won't get into. You're confused enough  )

You need a shut off valve at the appliance. (or within 6 feet in same room if using appliance connector)

Copper tubing or black iron through a wall or partition only, not appliance connector or rubber hose. (The connector or hose must be inspectable the entire length)
If going through cement, plastic sleeve over copper tubing. (to prevent contact with masonry that contains lime)

Your picture shows a BBQ single stage regulator. This is only used for a manual operated burner outdoors such as a bar-b-que grille. For indoor use you need a two stage regulator.

Notice the cap on your BBQ regulator screws on the top over the pressure adjustment screw. The appliance regulator is built the same way, but that cap when removed may have threads on the other side, so you remove it, flip it over and reinstall. The cap then puts different pressure on the internal spring. The cap is normally marked NAT and LP on the outside when in position. (back then some were painted red on one side) As stated above, if it a NAT regulator only and not adjustable, remove it so you get full system pressure to appliance. (An adjustable regulator in LP mode is actually blocked open inside to use full system pressure)

For oriface sizing;
If there is a data plate, you need to know the BTU of burners. Divide that BTU by the number of orifaces to come up with the needed BTU of EACH oriface. For example 1/64 drill is .0156 inches and allows 1700 BTU to pass at 11" W.C. (your regulator setting) So 1700 X the number of orifaces is the total BTU the 1/64 drill bit gives you. (I see 6 in your pic, so if it has 6 orifaces total that would be 10,200 BTU which I'm sure isn't enough). I would imagine your heater is in the 30,000 range?? Possibly 10,000 per burner maybe? It should be stamped somewhere. You can't simply make it as much as you like since burners and air mixing tubes are designed for a certain BTU.

The air adjustment is the last thing to adjust when the fuel pressure and oriface size is correct. It is an open slot where air enters and may not be adjustable if there is no movable cover or flap. In your case, the shape of oriface allows air to enter around it and the open burner tube is the air inlet.

An adjustable air inlet is at the oriface end of what is called the mixing tube. Air and fuel mix in this tube before the burner with holes. You have mixing tubes that are part of the burner where air and fuel mix. Gas from oriface displaces air in mixing tube and atmosheric pressure PUSHES are into void allowing air to mix with proper proportion of fuel. Height of burner as mounted may allow adjustment opening or closing area of incoming air.
Your circle is on the fuel manifold having nothing to do with air, it has 100% fuel vapor in it and through orifaces.


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## Billy62 (Jan 9, 2018)

coaly said:


> First, you can't use galvanized fittings.The 90* elbow looks like silver galvanized in your picture, unless it is stainless. They can be black iron or brass.
> 
> The cylinder must be outside the building. Stored outside the building, used outside the building. Never store it or bring it inside ANY building.
> 
> ...








Thanks for the advice...all the hose and tank stuff is just to see if it works and is all temporary..so what Im guessing from what you wrote, I should remove the valve from the bottom of the 1930 Humphrey and flip it over?...there are 10 nipples feeding the ceramics, one for each ceramic...I ordered a 1/64 bit as they are not stocked in any stores in my rural area and will negotiate the nipples when that gets here...I really appreciate you advise and help, hard to do over the net....if Im supposed to remove the valve (its pictured in the underneath photo) please let me know and I will remove, take some photos and upload for you to look at...sometime tomorrow Im thinking....please let me know if Im supposed to remove it?


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## coaly (Jan 10, 2018)

You don't flip the entire regulator (it's not a valve) over, you remove the screw on cap on the regulator and flip the cap over. (if it has threads on the other side) If no cap, or threads, remove the regulator from appliance. Could be a sealed regulator for NAT only if not adjustable.

1/64 is too small for 10 orifaces. That will only give you 17000 BTU total. I assume that size heater should be at least 30,000. You need to know what the burners are rated and give them the correct amount of fuel or it won't burn right. Is there a number stamped on the wrench flat of the orifaces? That number will correspond to the chart in the 4.0 Natural Gas column. You then know the BTU of each burner to use the correct drill size for LP at 11.

If no number on oriface;
WHAT IS THE TOTAL BTU of all burners? It should be marked somewhere. If you don't know that, you can't do it.

Take the total BTU, divide by 10 and that is the size oriface you need in each burner. This is a critical size and has to be exact.
If too small you won't cover the entire burner with flame, too large you will burn rich creating carbon monoxide. This is not a guess.

You also need to know the total BTU to be sure it will heat the area you're heating. Most new unvented heaters are 15,000 on low, and 30,000 or 45,000 on high to give you an idea of what it may be.


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## coaly (Jan 10, 2018)

Your question in pic "what is this" looks like the regulator but need better pics. The incoming gas line goes into regulator first.


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## Billy62 (Jan 10, 2018)

Billy62 said:


> Thanks for the advice...all the hose and tank stuff is just to see if it works and is all temporary..so what Im guessing from what you wrote, I should remove the valve from the bottom of the 1930 Humphrey and flip it over?...there are 10 nipples feeding the ceramics, one for each ceramic...I ordered a 1/64 bit as they are not stocked in any stores in my rural area and will negotiate the nipples when that gets here...I really appreciate you advise and help, hard to do over the net....if Im supposed to remove the valve (its pictured in the underneath photo) please let me know and I will remove, take some photos and upload for you to look at...sometime tomorrow Im thinking....please let me know if Im supposed to remove it?






OK..All the orifices (10) are stamped A...also on the adjustment cap is Humphrey Heater Co with 6 microscopic serial numbers that have been painted over 20-30 times...the manifold is stamped H 70....I appreciate your patience with me ...thanks...I uploaded pics of manifold and cap


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## Billy62 (Jan 10, 2018)

Billy62 said:


> Thanks for the quick response but Im a little fuzzy on some things...1.  is a gas grill tank (20lb) and regulator OK?....attached are pics..2..how do I know if the Humphrey regulator can be "flipped"?....The guy who sold me the ceramics said I probably need 1/64th holes and to peen the existing closed....I can do that, just a little afraid of ruining the heater if I get it wrong...attached are some pics..I will upload nipple pics in an hour....Thanks all!...Billy62






orifice marking...the holes are really small to me, but not sure


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## coaly (Jan 10, 2018)

The arrow in lower picture is pointing to the gas valve handle.

The regulator is what the gas supply line connects to.

The A stamp does us no good. I was hoping for the size number. Modern orifaces are now stamped with the oriface number or drill size as shown in left hand column of chart. Notice there is no such thing as a 1/64 oriface. That would be between a 78 and 79.If i had to guess, i'd guess your burners to be about 5000 BTU each which would be 50,000 Total. That would be a #70. That is twice the size of your 1/64. The company back then used a letter designation so the correct orifaces were installed in each appliance. I'm assuming you looked all over the appliance for a set of LP orifaces that can be screwed on the heater somewhere? Some companies put them in a cloth bag which would probably be long gone in your case.
Do you know what BTU the ceramic is for? I'm surprised there is no label or data plate giving BTU of heater. It could be in the form of 45K or 50K meaning 45 or 50,000 BTU.

The reason a pressure regulator is installed on an appliance (called appliance regulator) is in case the natural gas company regulator malfunctions and allows higher pressure to pass through. It is set approximately the same as the incoming gas from the natural gas line. This pressure is about 1/2 the pressure needed with LP. So if there is an appliance regulator on your heater, it can't be used while set for the lower natural gas pressure. That is about 1/4 psi or 4.0 W.C. compared to LP which is about 1/2 psi or 11 W.C.
Give me a picture of where the gas line connects and it should show the regulator.

When you are done, you are going to need to connect a manometer or U-tube gauge to the supply pressure line to both check for leaks and to make sure the gas valve closes fully. I would pull the gas valve apart and grease it (special gas valve grease) since you don't know when it was done last. It could be dry from sitting and the grease on the cone is what makes the seal. a pressure leak down test is the only way to leak check the system and appliance. How far are you from the PA border at RT.80 ? I can probably have this up and running in an hour.
The service valve required at appliance connection should have a test port as well which make it easy to verify you have a sealed system from cylinder to gas valve. Once you know it holds pressure during a 10 minute leak down test, you are safe to light the burners. I would not light them without doing that since you don't know if the gas valve on manifold leaks or any other parts of heater may leak.


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## coaly (Jan 10, 2018)

I just noticed your picture file names are Humphrey 60...... is that because there is a Humphrey 60 model number somewhere??


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## Billy62 (Jan 11, 2018)

coaly said:


> I just noticed your picture file names are Humphrey 60...... is that because there is a Humphrey 60 model number somewhere??




yes..when radiants are out it says Humphrey 60 impressed into the fireproof backing


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## coaly (Jan 11, 2018)

I would imagine that model designation is 60,000 BTU.
So oriface size should be #69 or .0292 inch that gives you 5956 each or 59, 560 BTU total. If you have other appliances on the same system with lower pressure under full load you could bump it up to the larger #68 since a lower operating pressure under load (such as 10") would bring output down from 67,000 with the 68 oriface.
I would go #69 to err on the side of lean being unvented.

I would also have a CO detector in the same building as appliance. You can always get spider webs in the intakes or low pressure from a variety of reasons that gives less than a clean burn.

Did you remove this heater from a Natural Gas line so you are sure it was set up for Natural? Those orifaces look small for Natural 60,000.

You can now do the calculation measuring the square inch area of each oriface to compare with square inch area of #69 round hole. If it is the same, they are for LP, Nat will be almost double the size.


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## Billy62 (Jan 11, 2018)

There are no other LP or gas appliances in the house...Im assuming its natural gas as it does not work correctly when I hook up the LP, that the reason Ive been asking on this site..I doint know what #69 means..please remember your dealing with a sign make/ carpenter at this end, all this calculating stuff gives me a headache..I talked to the guy at Humphrey (yes, the original Humphrey company, they actually called me back) and he said he has restored 10-15 of these and he said, as all of you have said, its in the hole size...his advice - measure present openings with micrometer or pin guage (of which I do not have)..take that number and divide in half, match that to a drill bit, solder holes closed, drill with the new bit, install and sit back and feel the heat (kidding on the last part)..he said if it is too low, use the next bigger bit....he said he never messed with any of his control valves...I dont know...Im beginning to think I should try and sell as is (natural gas) and see if I can recoup some or all of my money and just buy a Home depot gas log insert..but I HATE giving up on something after I start...is anyone out there within 100 or so miles of Philly PA that might be able to get this thing running?


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## coaly (Jan 11, 2018)

My first response on post #2 of this thread has the oriface chart you need. Most of my posts refer back to it. You need a good understanding of that chart first.
The right column is LP pressure and the BTU each size is for.
Go down the chart to the nearest size to give you 6000 BTU per burner. That is a #69 oriface drill number which is a .0292 drill bit. (notice it is 10 sizes larger than your 1/64 guess)
Peen them shut with them on manifold, (to prevent damage to threads) or solder shut, (gas service men don't have soldering equipment with them in the field, we peen them shut, they are soft brass) redrill to #69 size and you have the correct oriface size for 60,000 BTU  X 10 burners.
That MAY already be what you have! My last sentence in my last post is to confirm that.

He is correct in sizing orifaces but you didn't mention pressure.
The second thing to convert gasses is the correct PRESSURE.
You need 11inches Water Column gas pressure supplied by your regulator to the appliance, through the gas valve on appliance and to orifaces. If it has an appliance regulator set for Natural, it will reduce the pressure to half of what you need for LP.

*The basics are Natural Gas operates at half the pressure of Propane and uses a hole twice as large.* IF this heater has a regulator on it AND the regulator is set for Natural, you will need to adjust to LP pressure or *remove it* so it gets full system pressure from your regulator at cylinder.

If you are guessing you need to convert, you could be guessing the wrong problem. What did it do when you tried to light it? (which I wouldn't do until you pressure test it) If it is set up for Natural Gas it will burn with a huge yellow flame. (outdoors I hope)

If there is anything on this thread you don't understand, ask, or take the appliance to your local gas company to service it for you.


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## Billy62 (Jan 11, 2018)

coaly said:


> My first response on post #2 of this thread has the oriface chart you need. Most of my posts refer back to it. You need a good understanding of that chart first.
> The right column is LP pressure and the BTU each size is for.
> Go down the chart to the nearest size to give you 6000 BTU per burner. That is a #69 oriface drill number which is a .0292 drill bit. (notice it is 10 sizes larger than your 1/64 guess)
> Peen them shut with them on manifold, (to prevent damage to threads) or solder shut, (gas service men don't have soldering equipment with them in the field, we peen them shut, they are soft brass) redrill to #69 size and you have the correct oriface size for 60,000 BTU  X 10 burners.
> ...




When lit on Propane I can get either a yellow flame (low) or a blue flame..the blue flame seems to run best at about 2 inch height up from the burner..it seems to be not high enough to get the ceramics to glow as I know they should.  As a blue flame it can get really high but starts smoking.
I dont know if any gas service people in my area will work on a 1930's appliance, although I haven't asked yet.


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## Billy62 (Jan 11, 2018)

Billy62 said:


> When lit on Propane I can get either a yellow flame (low) or a blue flame..the blue flame seems to run best at about 2 inch height up from the burner..it seems to be not high enough to get the ceramics to glow as I know they should.  As a blue flame it can get really high but starts smoking.
> I dont know if any gas service people in my area will work on a 1930's appliance, although I haven't asked yet.


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## Billy62 (Jan 11, 2018)

This is a photo of the heater burning on propane, notice blue flame..is this correct?


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## coaly (Jan 11, 2018)

Yes that is correct. It should only be blue.

If it were set up for Natural gas it would be a big yellow fire ball.

If this had a regulator set for Natural gas pressure you wouldn't get a very high flame. It would be very low only.

Take it outside and burn it off on high. It's going to smell and smoke until clean from dust, finger oils etc...

Don't bring the Propane cylinder back in the building. It is illegal to take inside ANY building. Ever.

Gas company or service person should not have a problem working on it, but may advise it is against code to use it.

Law says if you as the expert in the field puts an appliance back into service, you are liable for any damages done by it since it was in a "safe" condition not working before you fixed it. Go figure.

I retired from my own Propane service business after 25 years and converted many built before UL listing began. (UL testing was around, it didn't cover stoves and heaters until almost 1980) It should have a pilot and pilot safety valve installed which shuts the gas off coming into appliance if pilot goes out. Back when I was in business, PA wasn't under the International Family of Codes we are today which states "All appliances must be UL Listed and approved". Period. An appliance is only Listed with a UL tag affixed to appliance. It would only be allowed if it were in an existing installation, not a new installation. This is almost all states now and most insurance companies will require appliances to be UL approved no matter when they were installed.

The correct thing to do first is to put a gas gauge that shows pressure in inches of Water Column on the system. (called a manometer or you can make your own U-tube gauge easily with vinyl tubing) Make sure gas valve on heater is off, then turn supply valve at tank on and back off again so system is pressurized but turned off. Turn on gas valve very little on heater and watch gauge until it starts to drop, closing quickly when it starts to drop, showing a lower pressure than 10" Water Column on gauge. This must hold the same pressure for 10 minutes without dropping. This tests the gas valve on heater as well as all fittings in system and parts of heater. It is known as a legal leak down test and must be preformed before any fuel company would supply fuel to the appliance. It also guarantees there are no leaks and it is safe to light the appliance.
This protocol must be followed* every time* a new system or appliance is installed. You simply can't soap everything, everywhere, the gauge don't lie. It is then safe to light and with gauge on system you set the regulator to 11" W.C. with burner on high. This is called pressure under load. Shut system off at supply valve and remove meter from test Tee or test port on service valve. (valve where LP line connects to heater- see prior posts) Turn on at supply valve and soap the test fitting, cap or plug where gauge was connected.


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## coaly (Jan 11, 2018)

DO NOT run it with yellow flame. That is a carbon producing flame that will make a black mess on everything from ceramics, the heater, to your lungs.
You want all blue.

Don't forget a CO detector in the same area as heater. You may find high readings depending on flame adjustment.
Codes do not allow open flame heaters in garages unless installed at certain heights. (gasoline fumes drop) Garage floors now must be a foot below living level, so follow codes that pertain to open flame use.


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