Kuuma VF 100 not heating my house! Help!

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Dan,
I read your original post and noted that you moved your barometric damper from 2 1/2 to 4 1/2 because the damper flap was flapping open. By increasing the number to 4 1/2 you are increasing the draft "to the furnace" which in turn will draw more heat up the chimney. I would probably go back to at least #3 since you have a fairly tall chimney. Secondly, I wouldn't focus too much on whether the barometric damper flap is moving. Sometimes it will be totally still (not moving) in a closed position, and other times it might be standing continually open( on windy days). I agree that you may want to purchase a monometer to monitor your draft.
I also agree that the biggest variable is the wood. Lamppa recommends wood between 18 and 28% moisture because this is what the EPA says the furnace must be able to burn cleanly, and the furnace must be certified to these moisture readings. But actually around 14% up to around a high of around 24% seems to be optimal. I did notice that last year when our wood was at only 8% moisture we only got around 5 hours of burn time with the Kuuma. But this year with the same furnace, same type of wood (birch), but at around 24% we consistently get around 13 hours. I agree that wood that is higher in moisture (over 24%) will consume Btu's to drive the extra moisture off the wood.

When you load your furnace - does the furnace go down to a small "c" on the control? With seasoned wood it will normally hit small "c" in anywhere from 15 minutes to 35 minutes. Higher moisture wood may never hit small "c".
We also agree with the importance of your cold air return. I know we call it cold air, but we want this air as warm as we can get it. If you are drawing from the basement, try to draw the air from up above the blower. If you attach to your home's cold air return - you may even want to insulate this cold air ducting.
I agree with everyone else, once you get this furnace tuned to your home, it should provide years and years of very comfortable heat.
Dale
 
What s- "baffles are in place in the HX"
The baffles in the top...that you have to remove to clean the HX...look it up in the manual, page 24
Just make sure they are properly in place.
 
I am heating a similar setup. Roughly 1900 sq ft ranch with full basement in Maryland. It's 26 degrees here now and it's 72 inside with the VF100 on low right now. The one difference is I have my complete HVAC return going through the VF100 so I can draw warmer conditioned air through the return to the VF100. I have two Normally Open / Power Closed dampers with a set of relays to section it off from the my heat pump for backup when I need it. My setup allowed me to duct both the heat pump and VF100 so they could share with the same ducts. I think the others may be on to something with the cold air return as the rest of your setup appears similar to mine. My house is built in 70's, so the insulation is average also. I also quit using the thermostat on the VF100 a year or so ago, and just let the fan run on low all the time. I feel it gives me more heat, but I can't really quantify that as I was warm either way. The one thing it did do, is equalize the temperature in my house better. I have cheap thermometers in each room and noticed a better balance in them when I started only running the fan on low. Don't give up, you will get there.
 
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I am heating a similar setup. Roughly 1900 sq ft ranch with full basement in Maryland. It's 26 degrees here now and it's 72 inside with the VF100 on low right now. The one difference is I have my complete HVAC return going through the VF100 so I can draw warmer conditioned air through the return to the VF100. I have two Normally Open / Power Closed dampers with a set of relays to section it off from the my heat pump for backup when I need it. My setup allowed me to duct both the heat pump and VF100 so they could share with the same ducts. I think the others may be on to something with the cold air return as the rest of your setup appears similar to mine. My house is built in 70's, so the insulation is average also. I also quit using the thermostat on the VF100 a year or so ago, and just let the fan run on low all the time. I feel it gives me more heat, but I can't really quantify that as I was warm either way. The one thing it did do, is equalize the temperature in my house better. I have cheap thermometers in each room and noticed a better balance in them when I started only running the fan on low. Don't give up, you will get there.
Thanks Burtman4! Yep, I fell confident from all of the responses that once I get warm air running through the cold air return it will be fine..I figured out that high setting on the blower was useless pretty quickly....It clearly pushes the air too fast through the Kuuma and it definitely heats better on low...I keep my thermostat set really low and that keeps that blower operating on low all of the time.
 
Dan,
I read your original post and noted that you moved your barometric damper from 2 1/2 to 4 1/2 because the damper flap was flapping open. By increasing the number to 4 1/2 you are increasing the draft "to the furnace" which in turn will draw more heat up the chimney. I would probably go back to at least #3 since you have a fairly tall chimney. Secondly, I wouldn't focus too much on whether the barometric damper flap is moving. Sometimes it will be totally still (not moving) in a closed position, and other times it might be standing continually open( on windy days). I agree that you may want to purchase a monometer to monitor your draft.
I also agree that the biggest variable is the wood. Lamppa recommends wood between 18 and 28% moisture because this is what the EPA says the furnace must be able to burn cleanly, and the furnace must be certified to these moisture readings. But actually around 14% up to around a high of around 24% seems to be optimal. I did notice that last year when our wood was at only 8% moisture we only got around 5 hours of burn time with the Kuuma. But this year with the same furnace, same type of wood (birch), but at around 24% we consistently get around 13 hours. I agree that wood that is higher in moisture (over 24%) will consume Btu's to drive the extra moisture off the wood.

When you load your furnace - does the furnace go down to a small "c" on the control? With seasoned wood it will normally hit small "c" in anywhere from 15 minutes to 35 minutes. Higher moisture wood may never hit small "c".
We also agree with the importance of your cold air return. I know we call it cold air, but we want this air as warm as we can get it. If you are drawing from the basement, try to draw the air from up above the blower. If you attach to your home's cold air return - you may even want to insulate this cold air ducting.
I agree with everyone else, once you get this furnace tuned to your home, it should provide years and years of very comfortable heat.
Dale
Thanks Dale! I do get the cold c every time I load the furnace with wood BUT I would feel very certain there are inconsistencies with some of my wood's moisture content levels. As I cut, split and dry my wood in the future, I'll take care to get the wood where I need it. This is my first season so some of the wood I have is 2 years of seasoning and some only one year.
 
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I assume you have turned the computer up, not still running on low...? (although from what you describe you should be able to leave it on low once you get things sorted out...mine rarely leaves low, even up here in NE OH)
 
Please tell me, now that you have tweaked the airflow through your furnace, are you able to get your living space AT LEAST up to 68 degrees consistently even when the outdoor temps are as low as around 14 degrees and up into the mid 20s degree range?

yep! It's actually 0° right now and the house is 73°.


What steps did you take to achieve your new results? I was told to run an open, vertical box from the back of the blower/filter housing area up to my floor joists in the basement...I'm actually thinking of running some custom stove pipes from the back of the blower/filter housing horizontally along the side of the unit with a bend that actually touches the top of the front door seam area of the firebox...the air around the firebox door is HOT, so I'm planning to try to set something like that up. Something where I can lift up the tubbing a bit when I need to open the door, then lower back in place when I have the unit running drawing that hot air from the furnace door area. I've actually seen a picture on the Kuma website of a customer that did this.

That's pretty much what I did, like I mentioned above.
 
Unfortunately, I am having the same issues with my new Kuuma Vapor 100...I've had this thing hooked up and operating for about 3 months now...Professional HVAC company installed and ducted..the whole 9 yards...a big production....I'm in Tennessee, so VERY mild winter weather. The Kuuma operates and heats the house GREAT when outdoor temps are in the 40s...When outdoor temps drop into the mid 30s, the Kuuma still keeps the house "kind of warm" at about 67 degrees..Yes, that's with the firebox blazing away... I researched wood burning furnaces for over 2 years, and carefully decided the Kuuma was the way to go...This was a VERY big investment for my family. My house is 1900 Sq. Ft. one story living space, ranch style house with a full basement. Nothing exotic. Big tall chimney as well. Oh yea, the Kuuma itself operates as advertised..Stack a bunch of nice seasoned hard wood in the fire box, and it gets HOT! The problem is, this heat is not transferring into nice warm air in the house..Today, the temp outside is 26 degrees (I know, 26 degrees is child's play compared to all of you in the Northern regions and Canada) but for Tennessee that's cold And the Kuuma still can't get my living space above 64 degrees!!! I "guess" it's the fan moving the air too quickly past the heating area just below the plenum because cold air is blowing through my floor vents...It's embarrassing quite frankly.... I know the stove pipe is hooked up correctly and the smoke runs out the chimney clear as glass, so even if this thing needs to be adjusted here and there, I do not see how I will ever get consistent 70 degree indoor heat from it..I just don't think it will happen. I can't find any reason why this thing can't produce heat in my house above 64 degrees on a day when it's 26 degrees outside....I guess (when I get the time to deal with it) I'll have the HVAC guys come out AGAIN to scratch their heads and offer little solutions...I do feel like to a large degree I have a very expensive paperweight that will at least keep us from freezing to death if the grid goes down...Word of advice, I just feel there are too many variables involved when trying to heat a home with a wood burning furnace...there are too many variables to take the gamble if you're looking to heat a home with this thing and no house/chimney/draft/ducting etc. are created equal. Results WILL vary from house to house for certain with these furnaces and that is VERY problematic. I know the folks that are getting 77 degrees inside their houses when the temps outside are below 0 are telling the truth..I trust the folks at Kuuma 100%, but man, this was a big expense and I'm just wasting beautiful firewood at this point. Thank God I still have my heat pump on my HVAC unit and propane set up. Serious advice: If you really are dead set on burning wood for heat, set up the cheapest unit you can, see how it works for you. If you like the results, many then after a few years of saving money, look at getting a Kuuma...maybe you'll have those excellent results all of us read about from satisficed customers...Maybe your house/chimney/ducting, and all the science that goes into this just works for you and your house. Thanks
On this furnace the blower fan blows air up the back of the stove [the coldest part] and right up into the plenum, it needs some sort of a baffel in there to move more air across the top and more to the front [where the heat is].The blower on low seems to put out too many cfm.Just a thought?
 
On this furnace the blower fan blows air up the back of the stove [the coldest part] and right up into the plenum
I beg to differ.
The blower on low seems to put out too many cfm
So adjust your supply duct pressure.
Or install more restrictive (higher merv) filters...