Can it be done? (Help!!)

[Stillson lives]

I have roughly 4000 sq ft to heat (tightly insulated new build house equally split between the main floor and finished basement) I am currently in the market for a wood furnace but most that are built for that size require an 8 inch flue, mine is only 6 inch.
I have been told that I can use the 6 inch flue anyway, even though the specs call for 8. Is it a possibility?
Currently looking at the charmaster or fire chief.

 

[brant2000]

I don't know much about them, but it appears the Kuuma units only require a 6" flue. (broken link removed) They are also very well reviewed on here.

 

[Stillson lives]

I don't know much about them, but it appears the Kuuma units only require a 6" flue. (broken link removed) They are also very well reviewed on here.

Thank you brant2000!

 

[brant2000]

I guess I incorrectly assumed that the 200 model is larger than the 100.

 

[brenndatomu]

The rule of thumb that I have always heard was that you can go up or down 1" from OEM specs on chimney size. That's assuming that everything else about your chimney is 100% as per OEM specs. A 6" might kinda sorta work on those wood hogs, but I'd bet my bottom dollar you are gonna have smoke rollout when reloading (an mama ain't gon like that!)
I was just gonna suggest the Kuuma VF100 (200 is gonna be too small for that footage) but brant beat me to it. Best wood furnace out there, and 6" flue too! I dare you to find a negative review on the Kuumas, I know I've never seen one!

(broken link removed)

 

[Stillson lives]

The rule of thumb that I have always heard was that you can go up or down 1" from OEM specs on chimney size. That's assuming that everything else about your chimney is 100% as per OEM specs. A 6" might kinda sorta work on those wood hogs, but I'd bet my bottom dollar you are gonna have smoke rollout when reloading (an mama ain't gon like that!)
I was just gonna suggest the Kuuma VF100 (200 is gonna be too small for that footage) but brant beat me to it. Best wood furnace out there, and 6" flue too! I dare you to find a negative review on the Kuumas, I know I've never seen one!

No smoking! (You're right, momma ain't gonna like that!) thanks again!

 

[velvetfoot]

The other thing is that 2000ft2 is finished basement? Maybe not as much heat loss there?

 

[Stillson lives]

The other thing is that 2000ft2 is finished basement? Maybe not as much heat loss there?

Yes it's all finished and insulated (I did it myself because I current have a wood stove down there) big mistake

 

[brenndatomu]

Yes it's all finished and insulated (I did it myself because I current have a wood stove down there) big mistake

Oh, in that case the 200 may work. If you call them they will be able to clarify that for you. Very helpful types they are. Family run business, outstanding customer service from what I hear
And I just added a link in my last reply for their site...

 

[Stillson lives]

Oh, in that case the 200 may work. If you call them they will be able to clarify that for you. Very helpful types they are. Family run business, outstanding customer service from what I hear
And I just added a link in my last reply for their site...

Thanks!!

 

[peakbagger]

My boiler came from a house with 6" flue and the boiler has and 8" flue. I got it for free and I had to repaint the front of the boiler as it was black above the lower hatch. I think it ran oaky once it got going but apparently it took quite awhile to get it to draft when lit off. I expect if you have an interior chimney with plenty of height you might be able to get away with it but any issues and it will be bear to light off.

 

[Mike Fromme]

It could be done... But it shouldn't be done.

 

[sloeffle]

PSG Caddy uses a 6" flue also. The Max Caddy might need a 8" flue though. You would need to verify on PSG's web site.

 

[laynes69]

Max Caddy also uses an 6" chimney. If using the oil option, then it's 7"

 

[3fordasho]

Second (or third) the recommendations for the Kumma 100 or max caddy. I'm heating 3400 sqft of 1982 vintage split level with a Drolet Tundra and it does just fine when temps stay above 10F. Lower than that and throw in some wind I light up my progress hybrid and burn that too. I knew the tundra was a bit undersized for my house but it was the only thing available quickly as I just moved into the place and wanted to minimize use of propane. Talked to the Kumma folks about the 100 but I'd still be waiting for it. The house is a quality build for 1982 (2x6 walls, some spray foam) but now has windows and especially doors that need some tightening up.

 

[laynes69]

Second (or third) the recommendations for the Kumma 100 or max caddy. I'm heating 3400 sqft of 1982 vintage split level with a Drolet Tundra and it does just fine when temps stay above 10F. Lower than that and throw in some wind I light up my progress hybrid and burn that too. I knew the tundra was a bit undersized for my house but it was the only thing available quickly as I just moved into the place and wanted to minimize use of propane. Talked to the Kumma folks about the 100 but I'd still be waiting for it. The house is a quality build for 1982 (2x6 walls, some spray foam) but now has windows and especially doors that need some tightening up.

For your footage, sounds like the Tundra is doing well. It's really hard to beat them considering cost and efficiency.

 

[3fordasho]

For your footage, sounds like the Tundra is doing well. It's really hard to beat them considering cost and efficiency.

It has not disappointed me so far. I did add a simple control- a omega digital temperature controller and J-type thermocouple in the flue stream about 12" above the exit.
It does two things: a NC relay contact is wired in series with the high temp limit, when flu temps reach 625F it opens the circuit and shuts the air inlet, hysterisis is set at 200F so it re-connects it at 425F. A feature that gives me alot of piece of mind that I never had with a manually controlled stove. I also have the temp controllers low limit alarm (NO contact) connected to the thermostat terminals to open the air inlet when flue temps drop to 225F with a 150f hysterisis- this ensures I don't come home to a furnace absolutely stuffed with coals after a work day. It still has plenty of coals for a restart. I know the thermostat should accomplish the same thing but with the size of the house if I put the thermostat at the desired house temp (say 69F) it would call for heat most of the time.

I also added the "hot tub" timer for re-loads -

 

[laynes69]

Yeah with our heating demand (2500sqft) with the Caddy, the thermostat works well. I've been eyeing the smartstove controller for some time, but I can keep the house within a couple degrees with the thermostat, and maintain long burns. How's your burntimes with that setup?

 

[sloeffle]

laynes, is this what you are talking about ?

http://inveninc.com

 

[laynes69]

Yeah, that's it. I was hoping eventually PSG comes out with something that can be added onto the Caddy line. With tighter emissions evolving, I have a feeling, this will pop up more and more. The smartstove controller has 5 different heat settings. If he could design a controller that will run a larger blower, then the blower could modulate based on plenum temperatures.

 

[3fordasho]

Loaded the furnace last night about 10pm, this morning at 6am the house was at 70F, outside temp 13F. Plenty of coals for a restart. After a long day (10hrs) the coals are still there but might need some kindling to help get if going quicker- house temps might have dropped off to mid 60's depending on outside temps of course. Now if I could just get it to automatically rake the coals to the front ;-) The key is maintaining temperature - with 3400 ft2 if you loose temp it's hard to get it back. I also have a very simplistic duct set up- return air simply pulled from the furnace room, 2-8" ducts from tundra to propane furnace plenum. I'll add a couple manual dampers when I want to run A/C. I'm sure some gains could be had by connecting the return air to the main furnace and having the appropriate dampers.

Yeah with our heating demand (2500sqft) with the Caddy, the thermostat works well. I've been eyeing the smartstove controller for some time, but I can keep the house within a couple degrees with the thermostat, and maintain long burns. How's your burntimes with that setup?

 

[sloeffle]

Yeah, that's it. I was hoping eventually PSG comes out with something that can be added onto the Caddy line. With tighter emissions evolving, I have a feeling, this will pop up more and more. The smartstove controller has 5 different heat settings. If he could design a controller that will run a larger blower, then the blower could modulate based on plenum temperatures.

Looked around on the SmartStove web board last night and it looks like (broken link removed to http://inveninc.com/SmartStoveForum/index.php?topic=66.0) in 2013. Not sure what ever came of it.

If PSG were to come up with a retro fit kit I would think they would need to change the blower motor to a DC / ECM motor in order to modulate the blower speed. The blower motor in my geo is a 1/2 HP ( you get can a 1HP also ) DC / ECM motor and the last time I looked for a replacement it was around $450.

I found that if I let the thermostat regulate the air inlet I end up with alot of idling after the temperature set point has been met. The servomotor opens the air inlet approximately 5/16 of an inch. Being a fan of the KISS method I have found that regulating the air with a small finish nail seems to work best after I get a good fire going. I can set the nail at the lowest point between the air inlet and the stove and usually wake up with a pretty decent coal bed and a warm house.