New furnace ( kuuma vapor fire 100) and new member here.

[Micdrew]

Wonder if your low limit switch is bad? I remember mine was bad right out of the box, the plenum temp was hitting about 160-180 before it turned the blower on, dale had me wire nut the switch closed until the new switch came in the mail, no problems since.

 

[Micdrew]

Mine was cycling a lot through the whole burn and it ended up being the low temp switch being bad. I had it turned all the way down to 105 (I think) and the when I put a temp probe in my plenum it appeared to cycling at 140-160. I was skeptical it was a the switch though, but i changed it anyway. With the new switch set at 110 the blower comes on and stays on for hours. Temp probe in the plenum is reading more in line with the switch now too.

Beat me to it 😂

 

[brenndatomu]

Mine was cycling a lot through the whole burn and it ended up being the low temp switch being bad. I had it turned all the way down to 105 (I think) and the when I put a temp probe in my plenum it appeared to cycling at 140-160. I was skeptical it was a the switch though, but i changed it anyway. With the new switch set at 110 the blower comes on and stays on for hours. Temp probe in the plenum is reading more in line with the switch now too.

I had a string of bad switches...the original, the one lamppa sent to replace wasn't really any better, the one I got off eBay was crap too...I replaced it with a Honeywell FLS (fan limit switch) that I had laying here and that was the end of it.
Lamppa said they got a bad batch of switches at one point there...I think I recall they ended up switching brands then...that's been a few years back though

 

[Erichomeowner]

Mine was cycling a lot through the whole burn and it ended up being the low temp switch being bad. I had it turned all the way down to 105 (I think) and the when I put a temp probe in my plenum it appeared to cycling at 140-160. I was skeptical it was a the switch though, but i changed it anyway. With the new switch set at 110 the blower comes on and stays on for hours. Temp probe in the plenum is reading more in line with the switch now too.

Was that the little snap switch that you replaced? Thanks

 

[burtman4]

Yes, it was the little snap switch.

 

[R Henderson]

I had a string of bad switches...the original, the one lamppa sent to replace wasn't really any better, the one I got off eBay was crap too...I replaced it with a Honeywell FLS (fan limit switch) that I had laying here and that was the end of it.
Lamppa said they got a bad batch of switches at one point there...I think I recall they ended up switching brands then...that's been a few years back though

Is the Honeywell fan limit switch you used more similar to the one that the VF uses for a high limit?

Mine seems to be working but it's only been burning a few weeks.

 

[brenndatomu]

Is the Honeywell fan limit switch you used more similar to the one that the VF uses for a high limit?

Mine seems to be working but it's only been burning a few weeks.

Yes.

 

[R Henderson]

Today I decided to take a look at the vapor fire 100s internals, it had been burning 24/7 for 3 weeks when I left it go out yesterday to adjust the door after break in of gasket. The chimney liner itself was clean actually still somewhat shiny, however my stove pipe did have some build up that I'm not sure about. I'll put some pics up and get your alls take on if this is alright or should I make any adjustments.

First pic is in rear of furnace, 2nd is chimney thimble, 3rd and 4th is furnace end of stove pipe, 5th is chimney end of stove pipe, 6th is furnace outlet. As a whole the top side surfaces are more shiny black? Creosote? The bottom sides have the debris I can brush most loose its more like fine dust black and brown color. Heat exchanger did have a good dusting of white fly ash.

 

[brenndatomu]

I don't see anything that would bother me...

 

[R Henderson]

I don't see anything that would bother me...

The main thing I was concerned about was in the last picture the glossy stuff at the top, but it seemed odd that it was more gunk closer to the furnace and the chimney which I assume would be cooler was clean all the way to the top. This picture is what came out of the stove pipe.

 

[R Henderson]

I think I may have a faulty low limit switch (the one mounted on the front up high on plenum) I had a fire going from Thursday till Sunday afternoon and was going to let it go out with temps in 60s for a few days. Yesterday my blower stayed running long after the fire was out and coals and turned to dust, plenum was cool to the touch top and bottom, computer was still on "3" but I suspect because the firebox holds heat so well. I lifted the front good off and it wasn't all that warm so I shut the breaker off went back a couple hours later turned breaker back on and blower kicked on instantly. Tried breaker again about 6am this morning and when turned on the blower didn't run this time.


Do you all think the switch may have reset itself after being off awhile or is the switch on its way out? I did read on here of some experiencing trouble with them. Other than that though the furnace is still running along nicely with plenty of heat ( only needed low so far) and get pretty good times between reloads.

 

[brenndatomu]

Do you all think the switch may have reset itself after being off awhile or is the switch on its way out?

Sounds like a bad one...not switching at the temps it should, but does work at extremes...

 

[R Henderson]

Sounds like a bad one...not switching at the temps it should, but does work at extremes...

Alright I figured it was I am going to call and see if they'll send me another should be a warranty part as I ordered it in July. I do however still have the Honeywell fan limit switch with the spring and probe off my old furnace would likely have to readjust it.

Is there any real hazards with refiring the furnace with the blower running constant or should I get a fire going and just plug into the current switch to turn the blower on? Or just wire nut it together while I'm using it.

Will probably have to build fire by Thursday or Friday were getting big temp swings here 66 today high of 36 on Friday.

 

[brenndatomu]

Alright I figured it was I am going to call and see if they'll send me another should be a warranty part as I ordered it in July. I do however still have the Honeywell fan limit switch with the spring and probe off my old furnace would likely have to readjust it.

Is there any real hazards with refiring the furnace with the blower running constant or should I get a fire going and just plug into the current switch to turn the blower on? Or just wire nut it together while I'm using it.

Will probably have to build fire by Thursday or Friday were getting big temp swings here 66 today high of 36 on Friday.

I'm sure they'll send you a new one...but I don't regret installing the Honeywell on mine.
I'd say you could bypass the switch for a day or two if needed...can't imagine how there'd be any real danger in that...

 

[R Henderson]

Just spoke with Dale about an hour ago and they are sending out a new switch, will just bypass the switch if I need a fire before it comes in.

Thank you again for the information, I'm going to save my old fan limit switch and will probably take that approach if it needs it again after the warranty is out.

 

[Spartanbball54]

Hello Everyone. New member and first post. I've been browsing anonymously for a few years.

Before purchasing a Kuuma Vapor Fire I'd like get some input from you guys.

I have a walkout basement and the least disruptive and most cost effective place to install a class A chimney is on the walk out side of the basement. But that will put the VF about 25' from my existing natural gas furnace. Is that too far away?

The hot water tank and existing gas lines prevent me from running a 16" round line directly into the plenum.

If this placement isn't too far from the existing furnace could I run two 8" line into each trunk line? I have trunk lines running in opposite directions from the existing furnace, like a "T"

I've included a picture.

I have an HVAC guy helping out with installation.

 

[brenndatomu]

Hello Everyone. New member and first post. I've been browsing anonymously for a few years.

Before purchasing a Kuuma Vapor Fire I'd like get some input from you guys.

I have a walkout basement and the least disruptive and most cost effective place to install a class A chimney is on the walk out side of the basement. But that will put the VF about 25' from my existing natural gas furnace. Is that too far away?

The hot water tank and existing gas lines prevent me from running a 16" round line directly into the plenum.

If this placement isn't too far from the existing furnace could I run two 8" line into each trunk line? I have trunk lines running in opposite directions from the existing furnace, like a "T"

I've included a picture.

I have an HVAC guy helping out with installation.

OH! IO!
Whereabouts are you in central OH? Wayne county here.
25' is a pretty good run...I would make sure to not skimp on the size at all, a lil oversize is good...(2) 8" round going to each half of the T would probably work...or it may be cheaper to just go with one standard rectangle duct to each side, 8x12-16, whatever pencils out the best. I'd suggest planning on insulating those ducts too, real long runs can have a lot of heat lost to the basement...and the VF doesn't have real high duct temps to begin with, like the wood furnaces of old... tortoise vs hare type of thing.
And just a thought...might be faster/easier/cheaper/better to move the water heater...?
And just so we don't hijack @R Hendersons thread, I would ask the mods to move your post and my last one to its own thread...you'll likely get better participation that way too (change of topic/title might draw in some new/different/more people)

 

[R Henderson]

The VF 100 is still running along pretty good however our most recent Arctic blast I have been experiencing some loss of efficiency.

What has been happening is we have had several days of near or below zero and my chimney ever since I have hooked up my Dwyer I realized my chimney drafts harder than I originally thought and even with the barometric damper on its lowest setting I'm still getting 0.5-6 easily and noticing that my supply temps seem cooler and just checking my flue pipes with a laser thermometer I am getting higher readings than normal so I suspect more heat is being sent up the chimney. I've played with the computer but it generally does it on low or even up to just under medium.

So my question is how would I go about lowering the draft even more? Is another old school flapper damper a possible approach or would that cause problems? I thought about adding weight to the BD but would rather not risk damaging it I considered tying it slightly open but thought that could down draft if conditions were right.

 

[R Henderson]

Currently tonight as of now the BD is on its lowest weight setting the winds are low to calm and in my valley area the low tonight is expected to be approaching zero it is currently 8 out now and my Dwyer is showing 0.5

 

[JRHAWK9]

The VF 100 is still running along pretty good however our most recent Arctic blast I have been experiencing some loss of efficiency.

What has been happening is we have had several days of near or below zero and my chimney ever since I have hooked up my Dwyer I realized my chimney drafts harder than I originally thought and even with the barometric damper on its lowest setting I'm still getting 0.5-6 easily and noticing that my supply temps seem cooler and just checking my flue pipes with a laser thermometer I am getting higher readings than normal so I suspect more heat is being sent up the chimney. I've played with the computer but it generally does it on low or even up to just under medium.

So my question is how would I go about lowering the draft even more? Is another old school flapper damper a possible approach or would that cause problems? I thought about adding weight to the BD but would rather not risk damaging it I considered tying it slightly open but thought that could down draft if conditions were right.

I run a higher draft when it's cold out. I typically run -0.04" - 0.05" but increase that to -0.06" when it's cold out. It does waste more out the chimney, but I also see increased supply temps too, at the expense of more wood being consumed. If you are seeing reduced supply temps when it's cold out, more than likely it's because the increased heat load is lowering your house temp which then lowers your return air temp which then lowers your supply temps. It's snowball effect that I will also see when it gets very cold out. It's simply that your house is losing more BTU's than the furnace is supplying. It can happen mostly at the end of the burn cycle in the mornings when the house has the highest heat load while the furnace is putting out the least amount of heat.

Having numerous cold days in a row can make it challenging to heat for sure. Once the snowball effect starts (ie the house starts losing temperature), it can be very difficult to overcome. As now you not only have to put back into the house what the house is losing in real time, but also have to add more on top of that in order to gain on the house temp.....something that can be very hard to do.

To put it simply, you are not really seeing the loss of efficiency; you are seeing the exponential increase in heat load from the house losing heat exponentially from the extended cold temps. The first couple cold snaps I endured with mine I also thought the same as you. I asked myself why are my supply temps all of a sudden colder......it's because the return air temps are colder due to the house temp trending down.

If you have your Kuuma setup to where you can "play nice" with your LP/NG furnace, you can just simply set the house thermostat to whatever temp you want it in the house and let the LP/NG furnace fill in when necessary.

I have since did some tweaking to my cold air and air supply in order to keep my return air temps higher which then keeps my supply temps higher.

 

[brenndatomu]

The VF 100 is still running along pretty good however our most recent Arctic blast I have been experiencing some loss of efficiency.

What has been happening is we have had several days of near or below zero and my chimney ever since I have hooked up my Dwyer I realized my chimney drafts harder than I originally thought and even with the barometric damper on its lowest setting I'm still getting 0.5-6 easily and noticing that my supply temps seem cooler and just checking my flue pipes with a laser thermometer I am getting higher readings than normal so I suspect more heat is being sent up the chimney. I've played with the computer but it generally does it on low or even up to just under medium.

So my question is how would I go about lowering the draft even more? Is another old school flapper damper a possible approach or would that cause problems? I thought about adding weight to the BD but would rather not risk damaging it I considered tying it slightly open but thought that could down draft if conditions were right.

You could add a manual damper to the stovepipe, use that to lower the draft to the point where the baro can regulate things more normally.
A little magnet can be handy to adjust your baro up or down beyond factory adjustment too...clip it on the top of the flapper to drive draft down, toward the bottom to drive draft up.
When I see supply temps go down, and flue temps go up, I know it's time to clean the heat exchanger... I'll usually just do a quickie on it unless the weather warms up and I can get it cool enough to do it proper (but honestly that usually just done in the off season)
I made myself a custom scraper so I can clean things up half decent without having to stick my arm in there too much...can clean it when it's still pretty warm that way (like still some hot coals in the firebox)

 

[brenndatomu]

I don't recall if you have the return ducts hooked up or not, but if not you'll find that your return air temp from the basement can drop a lot when it gets good n cold out, that directly affects supply temps...better to pull return air from the ceiling if you can, it can be 10* warmer (assuming the return is not hooked up)

 

[R Henderson]

I don't recall if you have the return ducts hooked up or not, but if not you'll find that your return air temp from the basement can drop a lot when it gets good n cold out, that directly affects supply temps...better to pull return air from the ceiling if you can, it can be 10* warmer (assuming the return is not hooked up)

Yes that was a change I added early on I made a box where I'm drawing return air about 4-5 feet off the floor. It is likely that the HX could be needing cleaned it has went through a few cold starts the last couple months. Good to know about the manual damper or adding a magnet for weight to the BD.

Also as JRHAWK said I'm sure this house needs help in the insulation department I've noticed several frosty mornings the roof is melted sometimes even before sunrise. No other backup heat here besides baseboards in the bathrooms and all other rooms have electric wiring in the ceiling they called radiant with an adjustment dial in each room.
Apparently it was pretty common when the house was built in early 1970s.

 

[brenndatomu]

No other backup heat here besides baseboards in the bathrooms and all other rooms have electric wiring in the ceiling they called radiant with an adjustment dial in each room.
Apparently it was pretty common when the house was built in early 1970s.

My buddy's place had that...back in 2014 we had a cold winter and he said he had a $900 electric bill one month...he spent some big bucks to have nat gas brought in to the house, and a whole new forced air HVAC system retrofitted the following summer

 

[R Henderson]

My buddy's place had that...back in 2014 we had a cold winter and he said he had a $900 electric bill one month...he spent some big bucks to have nat gas brought in to the house, and a whole new forced air HVAC system retrofitted the following summer

I'm kind of surprised it still works as I've heard most of it failed early on, we use it some in the spring when it's warming up outside but you can feel the heat out in the open but if you're feet are under a table or something they feel cold, and it is terribly inefficient the last few years my grandfather was alive and lived here he used the electric soley ( he couldn't navigate the basement stairs for the wood furnace) i know he had some bills in the $900 range but he kept it about 80 so it likely ran constantly. We are considering some kind of second heat source, mainly for shoulder season or for if something happens in the future and I'm unable to do my own wood. However the VF consumption is so low that I could buy it easily I have only used about 1 chord this winter so far so definitely impressive.