The whole deal for a basement wood furnace

[brenndatomu]

You can make a damper by screwing some angle around the inside of the furnace plenum. Then clamp a pivot rod to 1 or 2 (as laynes said) pieces of sheet metal, install on top of the angles. Furnace blower will blow it open but block the flow from the Tundra

 

[roofyroo]

My main concern is everything being safe so small steps and suggestions have been great so far.

I've gone to the effort of laying out a schematic of our duct and vents. The house is old so there is no return apart from a vent in the stair wall leading down to the basement.
(broken image removed)
The addition that was built at some point is COLD! I managed to check under the floor and there is no insulation - it's just built off the ground. I'm sure at some point insulation will do some wonders there.

I don't think I am burning the furnace hot enough. I just added more wood and opened the air inlet damper and came upstairs with intention of heading back down in 5 minutes. I forgot and ended up going down to close the damper after about 15-20 minutes and the furnace is now raging and the hot air outlets are pretty warm. The house temp has gone up as well.
So in people's experience it's okay to leave the inlet damper open for that period of time? If I don't then it seems it isn't kicking out enough heat. This is all new to me so maybe this is normal.

 

[roofyroo]

Currently there is no:

• barometric damper installed on the chimney exhaust line
• 8" backdraft dampers on either hot air outlet from the wood furnace
• backdraft damper in the electric furnace

The electric furnace has a large sheet of cardboard covering the filter at the base to block hot air escaping to the basement.

 

[laynes69]

I run our furnace between 10-20 minutes before shutting it down. If it doesn't get up to temperature, it won't produce much heat.

 

[joes169]

So in people's experience it's okay to leave the inlet damper open for that period of time? If I don't then it seems it isn't kicking out enough heat. This is all new to me so maybe this is normal.

I've got a Caddy, which shares the same firebox design, but the damper door is controlled by the thermostat. When it gets down around zero degrees, it's not uncommon for the damper door to be open for 4-6 hours if it's not attended to overnight, etc... I'm not sure there's any reason you would have trouble leaving it open foran hour or two, unless the units are that vastly different?

On a side unit, I', pretty sure your duct work isn't up to snuff, as I believe the first 6' needs a minimum of 6" clearance to combustables (floor joists and wood beam in this case).........

 

[roofyroo]

Great thanks for your response!

I'm beginning to think that burning the furnace hot for a longer period would be fine. I was paranoid to begin with as this is new to me and obviously I don't want to burn the house down.

The thermostat is on my list so the control will be somewhat automatic.

Duct work is more than 6" away from anything as it's running the top third of the basement until it branches off, then it's near the ceiling.

Any tips on adding wood? Should I try and burn each load down before adding another load, or just keep adding here and there as needed? Big pieces in the middle or side or bury them down to the bottom of the coals etc?

 

[roofyroo]

Will burning with the damper inlet open use significantly more wood meaning the heat won't last all night because the furnace will need re-filling?

 

[laynes69]

Will burning with the damper inlet open use significantly more wood meaning the heat won't last all night because the furnace will need re-filling?

I wouldn't burn wide open with an unregulated draft. Especially on a full fresh load. After a while, burning with the damper open is okay. Even during peak demands, the damper shouldn't remain open for a long period of time. For sure, get a thermostat on the furnace. Even if it remains open for a long period, we still have coals and a warm home.

 

[roofyroo]

Any advice on a thermostat? I assume it doesn't need to be an expensive one for this purpose?

 

[laynes69]

No, I used a cheap digital thermostat for our furnace. I think I paid $20.

 

[DoubleB]

Any advice on a thermostat? I assume it doesn't need to be an expensive one for this purpose?

That's how I see it. Simpler is better here, since it's impractical to try to program a thermostat for a wood furnace.

If I have moist wood, or more commonly if I have small wood (that offgasses quickly), I'll burn with the damper wide open for even 60 minutes to burn off all the smoke, but just do a small size load to prevent it from overheating. Technically, there is an overtemp cutout that will shut the damper if hot air temp hits 160 degrees. I've never had that happen to me (that I know of).

In fact, even with a thermostat, it will run the damper wide open if temp is too low, without you even knowing, so I'm assuming the Tundra can take a good bit of heat.

Of course, I have some paint flaking off the front of my Tundra, presumably due to heat...

 

[DoubleB]

Also, if you are finding the temporary cardboard "damper" to be effective, you might consider putting the backdraft damper on the electric furnace air inlet. So cold air can come in to the electric furnace but not back out. Very accessible and lots of room to put in on. Effect is the same as putting it on top of the electric furnace.

However, . If there are enough air leaks, you'll get some hot air backfeeding through your electric furnace. I'm not smart enough to know if that is a problem. But I've heard people say that wood furnace hot air gets hot enough to mess up air conditioning coils, which I see that you have.

 

[brenndatomu]

Will burning with the damper inlet open use significantly more wood meaning the heat won't last all night because the furnace will need re-filling?

Yes

I wouldn't burn wide open with an unregulated draft.

+1 ^ ^ ^

Any advice on a thermostat?

Honeywell FocusPro 5000, works good with a wood furnace, can be had for $20 or less on fleabay...

 

[joes169]

I wouldn't burn wide open with an unregulated draft. Especially on a full fresh load. After a while, burning with the damper open is okay. Even during peak demands, the damper shouldn't remain open for a long period of time. For sure, get a thermostat on the furnace. Even if it remains open for a long period, we still have coals and a warm home.

Maybe the Tundra operates completely different than the Caddy, but do you see periods, when you need to "catch up" a few degrees after getting behind, that your damper door stays open for a few hours??

 

[STIHLY DAN]

I;m sorry but you really should finish the install before figuring out how to use it. Doe's this unit come with an install manual? It is specifically made for easy homeowner installation. This is like saying the car isn't running right but the wheels aren't on yet, I need an injector, and I have old gas. Why am I not going anywhere fast.

 

[laynes69]

It operates exactly the same, same servo, same damper. To be honest, our furnace doesn't get behind often. The only time we dropped below our setpoint at 72 overnight was recently with a nighttime low of -10°F with windchills aproaching 40 below. It was 68°F in the home when I woke and the furnace consumed a full firebox in 7 hours which I thought was very good. Instead of pushing the woodfurnace when I woke, I ran the LP for 1 cycle, about 10 minutes to bring the home at 71° then shut off the LP and the woodfurnace then maintained the home. We are looking at -14°F Thursday night and it may be the same scenario. This morning, it was -6° and 70 when I woke up from overnight. Within 15 minutes of loading the furnace, the temperature raised 1 degree and I closed the damper. From there it climbed and maintained 72 for when my wife got up. If it's that cold and there's a very heavy demand for heat, I won't keep it open the entire time. It wastes wood and pushes heat out the flue. Instead, let it get very hot where it starts to climb and close the damper. It should continue to produce alot of heat, while preserving wood. Once it gets close to the coaling stage and it's that cold, the damper pretty much remains open. The major difference between the two furnaces ( Caddy and Tundra) is the jacket. We have a large plenum opening which allows for excellent airflow thru our ductwork.

 

[joes169]

It operates exactly the same, same servo, same damper. To be honest, our furnace doesn't get behind often. The only time we dropped below our setpoint at 72 overnight was recently with a nighttime low of -10°F with windchills aproaching 40 below. It was 68°F in the home when I woke and the furnace consumed a full firebox in 7 hours which I thought was very good. Instead of pushing the woodfurnace when I woke, I ran the LP for 1 cycle, about 10 minutes to bring the home at 71° then shut off the LP and the woodfurnace then maintained the home. We are looking at -14°F Thursday night and it may be the same scenario. This morning, it was -6° and 70 when I woke up from overnight. Within 15 minutes of loading the furnace, the temperature raised 1 degree and I closed the damper. From there it climbed and maintained 72 for when my wife got up. If it's that cold and there's a very heavy demand for heat, I won't keep it open the entire time. It wastes wood and pushes heat out the flue. Instead, let it get very hot where it starts to climb and close the damper. It should continue to produce alot of heat, while preserving wood. Once it gets close to the coaling stage and it's that cold, the damper pretty much remains open. The major difference between the two furnaces ( Caddy and Tundra) is the jacket. We have a large plenum opening which allows for excellent airflow thru our ductwork.

Thank you for the great response. I don't want to infringe too much on the original poster, so I'll likely just start a separate thread of my my own set-up when I get a chance to upload some pictures. I have a few ideas on why I maybe seeing lackluster performance from my Caddy, but I'll look for some additional assistance in the near future here............

 

[martae]

The complexity of this "flue project" has sold me on outdoor wood boilers. Is there one that is a true downdraft wood gasification boiler? Or maybe a "basement" boiler in a small boiler house that would double as a wood shed. I like the idea of a straight, vertical six or eight foot flue, passing through nothing but a metal roof, and some fiberglass insulation.

 

[maple1]

The complexity of this "flue project" has sold me on outdoor wood boilers. Is there one that is a true downdraft wood gasification boiler? Or maybe a "basement" boiler in a small boiler house that would double as a wood shed. I like the idea of a straight, vertical six or eight foot flue, passing through nothing but a metal roof, and some fiberglass insulation.

That's not quite on the thread topic - but I'd say that's not reason enough to go OWB. Doing a flue is a one-time thing, keeping an OWB in wood is a lifetime-of-the-boiler thing.

 

[brenndatomu]

The complexity of this "flue project" has sold me on outdoor wood boilers.

flue project?

 

[roofyroo]

Also, if you are finding the temporary cardboard "damper" to be effective, you might consider putting the backdraft damper on the electric furnace air inlet. So cold air can come in to the electric furnace but not back out. Very accessible and lots of room to put in on. Effect is the same as putting it on top of the electric furnace.
However, . If there are enough air leaks, you'll get some hot air backfeeding through your electric furnace. I'm not smart enough to know if that is a problem. But I've heard people say that wood furnace hot air gets hot enough to mess up air conditioning coils, which I see that you have.

I wanted to quote all the above so it makes sense to anyone else, but specifically wondering about the last comment to do with hot air messing up the air conditioning coils. Any other input on this? I love the idea of putting a backdraft damper where the filter is as it would make my life SO much easier!

 

[brenndatomu]

Since the coil is not in the plenum right on top the Tundra, I think it will be fine, temp has dropped a bit by the time it gets over there. The plastic drip tray that I mentioned before, now that I think about it, will probably be OK too. Just FYI, Yukon says that the AC coils are fine being mounted over their furnaces, and they are certified to run during power outage, so we are talking serious heat buildup there! No plastic drip pans on a Yukon! If you have the room to do backdraft damper in filter housing area I would think it would work fine

 

[roofyroo]

Thanks for your input!

 

[DoubleB]

I think Brenndatomu's assessment sounds pretty realistic. I didn't mean to cause alarm with the ac coil, but something to pay attention to since I don't know much about the risks.

I try to cover my bases on these kinds of things...if I was in your shoes it's pretty easy to stick a thermometer in the a/c coil and see what you get (with the cardboard installed). Could even pull the plug on the Tundra and measure temps then too without a blower. Assuming you measure reasonable temps on the coil, then I'd do the backdraft damper on the electric furnace cold air intake for the simplicity and access.

 

[Smoke Signals]

Also, if you are finding the temporary cardboard "damper" to be effective, you might consider putting the backdraft damper on the electric furnace air inlet.

+1