Kuuma Vapor Fire 100 - Setup Help

[Pustiki]

I installed a manual damper this year on the plenum and saw a drastic increase in supply temps,

Do you have any more details on this? Is the idea to create some restriction in the plenum?

 

[Micdrew]

Do you have any more details on this? Is the idea to create some restriction in the plenum?

Sorry I should of said register, Im blowing hot air into the basement which is then being recycled through the furnace boosting my supply temp, the warmer the return air the hotter the supply. From your pics it looks like you’re drawing your return for the basement?

 

[brenndatomu]

Do you have any more details on this? Is the idea to create some restriction in the plenum?

You have no dampers on your supply lines, or adjustable registers?

 

[brenndatomu]

Sorry I should of said register, Im blowing hot air into the basement which is then being recycled through the furnace boosting my supply temp, the warmer the return air the hotter the supply. From your pics it looks like you’re drawing your return for the basement?

Wouldn't that be like perpetual motion?

 

[Pustiki]

From your pics it looks like you’re drawing your return for the basement?

Yes, generally. Air temp in basement is between 62F-65F, floor to ceiling. It’s just being warmed by whatever heat comes off the furnace door.

You have no dampers on your supply lines, or adjustable registers?

The floor registers are adjustable. No other dampers in the ducting…

 

[brenndatomu]

The floor registers are adjustable. No other dampers in the ducting…

Partially closing those would produce static pressure in your supply system...it could be set by using the manometer...I've never seen Lamppa mention it, but most wood furnaces call for about .2" WC (max IIRC)

 

[Micdrew]

Wouldn't that be like perpetual motion?

Correct but its a 4x10 register that I keep partially closed, the original reason was to help shed heat in a power outage but I noticed that the return air had jumped about 5 degrees from 75 to 80 bumping my supply temps to about 103 with the computer on low and the blower on low.

 

[Pustiki]

Partially closing those would produce static pressure in your supply system...it could be set by using the manometer...I've never seen Lamppa mention it, but most wood furnaces call for about .2" WC (max IIRC)

I made this adjustment over the weekend and think that did improve the heat delivery. Maintained 69-70F on smaller more frequent loadings. Computer set to High. Not quite as cold as last week, but we did have windchill values of 8F outside, so I took that as a win.

 

[Pustiki]

Small updates. The manometer arrived yesterday and I began playing around with that. Probably need to do some more reading on how to use a manometer...

Testing through the baro-damper (12 inches up from stove connection), I get a draft reading of .03-.04.
Testing through the pilot holes in the computer controlled damper, I get .04-.05
Testing through my chimney cleanout door, I get .03-.04
Also used the tool to set all of the registers as close to .02 as I could.

I guess this confirms the need for an insulated chimney liner.

At 30F outdoor temps, house is back to maintaining 70F indoors with the computer on medium and a half load of two or three splits.

 

[brenndatomu]

Testing through the baro-damper (12 inches up from stove connection), I get a draft reading of .03-.04.
Testing through the pilot holes in the computer controlled damper, I get .04-.05
Testing through my chimney cleanout door, I get .03-.04

Drill a hole, install it between the furnace and the baro

 

[JRHAWK9]

Regarding draft, this is what I have learned over the years, at least in my situation. We have very dry wood and when it's not near/below zero I can get away with running a lower draft all the time (-0.35 to -0.40"). However, when it gets colder out, I have to bump it up to -0.06", otherwise at the second half of the burn I won't get enough BTU's in the house due to, I'm assuming, the lower volume of flue gasses moving through the HX to pull heat from. You should see better results when you get your draft increased. Also, play around with your return air. Try to get it as warm as possible, this will increase your supply air temp. We have a house which is not very heat efficient, but I have my return/supply air system setup pretty well optimized for our place. Slowed blower WAY down to increase supply temps. This house does not heat very well with high volumes of 100° - 110° air (where I was at with the OEM blower setup). It needs lower volumes of hotter air (120° - 140°). It's interesting to me that even though the furnace is producing the same amount of BTU's, it's HOW those BTU's are being sent to the house which made ALL the difference in the world for me.

 

[Wiwarm]

The ductwork down there is admittedly a mess. Whoever did that install made some crazy choices. I’m kind of retrofitting and I’ll address that over time. Air temp at the ceiling is around 65F. I just moved my thermometer to see where it’s at on that return. Wondering if it’s worth abandoning the return and grabbing air from ceiling height.

The flue has a 6” to 8” adapter on it inside the clay thimble. That adapter is tight to the walls of the clay and much further in than that fiberglass. Was a temporary test to see if it improved draft in case of a leak. It’ll go away when I get the new liner. It’s not fireproof, but I believe combustion temp is at least 1000F. I just didn’t have rock wool on hand.

I moved the low limit this evening and re-set it to 105. Anything higher than that and the fan will cycle on off. The temp in the living space is holding 68, but it’s “only” 21F outside now.

I would say your "cold" cold air return is a very likely contributer to your issue. The less you have to heat the return air the better. I would as you suggested bypass the cold air return to troubleshoot and try using the air closest to the ceiling in the basement. Check these results and go from there