Caddy wood add-on furnace help

[KeithTalent]

Hey all,

We just bought a house in a colder climate and the heating system is a gas furnace with a Caddy add-on wood burning furnace. I'm a complete noob when it comes to this stuff so was hoping y'all could assist me in getting this running properly.

I've started fires the past three days, but no matter how big I make the fire or what I set the thermostat at (it's an SBI wired thermostat) the temperature never seems to go above ~66F and if I crank the SBI and the gas thermostat, it mainly just pumps gas (at least as far as I can tell). I bought new batteries for the thermostat and that did not make a difference.

I tried reading through the manual but it really did not help at all. Does anyone have any ideas on what I might be doing wrong?

Thanks in advance for the help.

KT

 

[U.P.Boiler]

Hey all,

We just bought a house in a colder climate and the heating system is a gas furnace with a Caddy add-on wood burning furnace. I'm a complete noob when it comes to this stuff so was hoping y'all could assist me in getting this running properly.

I've started fires the past three days, but no matter how big I make the fire or what I set the thermostat at (it's an SBI wired thermostat) the temperature never seems to go above ~66F and if I crank the SBI and the gas thermostat, it mainly just pumps gas (at least as far as I can tell). I bought new batteries for the thermostat and that did not make a difference.

I tried reading through the manual but it really did not help at all. Does anyone have any ideas on what I might be doing wrong?

Thanks in advance for the help.

KT

Does it have a switch to turn the blower on the caddy On?


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[NaturalCauses]

It seems counter intuitive, but the furnace heats better when the air damper is closed. When the damper is open most of the heat goes up the flue before it has a chance to transfer to the plenum via the heat exchangers. Try getting the fire going hot/your load of wood charred then turn down the thermostat to close the damper and see how it performs. Also make sure your wood is seasoned enough. These furnaces love dry wood.

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[brenndatomu]

Hey all,

We just bought a house in a colder climate and the heating system is a gas furnace with a Caddy add-on wood burning furnace. I'm a complete noob when it comes to this stuff so was hoping y'all could assist me in getting this running properly.

I've started fires the past three days, but no matter how big I make the fire or what I set the thermostat at (it's an SBI wired thermostat) the temperature never seems to go above ~66F and if I crank the SBI and the gas thermostat, it mainly just pumps gas (at least as far as I can tell). I bought new batteries for the thermostat and that did not make a difference.

I tried reading through the manual but it really did not help at all. Does anyone have any ideas on what I might be doing wrong?

Thanks in advance for the help.

KT

Little confused here...so the Caddy Tstat doesn't work?
As mentioned above, the Caddy doesn't perform well at all on anything other than DRY wood...like 2 or 3 years cut/split/stacked dry.
And just FYI, wood furnaces do much better at maintaining the house temp than they do raising it much...especially when the house temp has fallen a lot.
@laynes69 might have some good input here too...

 

[KeithTalent]

Does it have a switch to turn the blower on the caddy On?


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Not that I've seen.

It seems counter intuitive, but the furnace heats better when the air damper is closed. When the damper is open most of the heat goes up the flue before it has a chance to transfer to the plenum via the heat exchangers. Try getting the fire going hot/your load of wood charred then turn down the thermostat to close the damper and see how it performs. Also make sure your wood is seasoned enough. These furnaces love dry wood.

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The wood is good based on what I've read and discussion with neighbours. I'll try turning down the thermostat and see if that helps, but I'm failry certain it will plateau at around the same level again.

Little confused here...so the Caddy Tstat doesn't work?
As mentioned above, the Caddy doesn't perform well at all on anything other than DRY wood...like 2 or 3 years cut/split/stacked dry.
And just FYI, wood furnaces do much better at maintaining the house temp than they do raising it much...especially when the house temp has fallen a lot.
@laynes69 might have some good input here too...

The thermostat for the Caddy does indicate the temperature of the room, so in that respect it is working, but for some reason it does not seem to kick the heat above a certain level. Maybe what you are saying is right though, in that we need to bump up the gas and wood at the same time then have the wood going to try and maintain that heat?

KT

 

[brenndatomu]

So when you turn the Caddy Tstat up does the damper on the front of the Caddy open?

 

[KeithTalent]

So when you turn the Caddy Tstat up does the damper on the front of the Caddy open?

Not sure. They are pretty far apart. I'll test that.

KT

 

[laynes69]

How is the furnace installed? Series with a shared central furnace blower, or parallel where both units have a separate blower? After loading and getting a hot furnace, you can close the damper and it should produce some heat. Ours as others do not run well on the stock air, unless I'm burning softwood. I run ours with a little extra air, especially during these sub zero days. Could you post a pic of your setup, and what's the size of your home?

 

[KeithTalent]

How is the furnace installed? Series with a shared central furnace blower, or parallel where both units have a separate blower? After loading and getting a hot furnace, you can close the damper and it should produce some heat. Ours as others do not run well on the stock air, unless I'm burning softwood. I run ours with a little extra air, especially during these sub zero days. Could you post a pic of your setup, and what's the size of your home?

Series. From my reading series is the only thing allowed in Canada (where I am). Our place is a bit over 3,000 square feet. Here are some pics:

Lit Up

Unlit

Close up of Caddy

Rear view of setup


KT

 

[laynes69]

3000 square feet is a bit for a Caddy, unless that includes the basement. We are at 2500 square feet (10' ceilings) plus a basement (1200 sq.ft), and it's almost too much. Still we haven't been below 70 degrees and it's fell below zero here.

Dry wood is key, and like mentioned above, running with the damper open is not the way to operate. You can use a paperclip on the side of the primary damper to allow some additional air when the damper closes. Get it hot, then close the damper and it should cruise. I also do not see a barometric damper, do you have one?

If your unsure if the central furnace is running, feel the ductwork connecting the two, if it's warm, then it's firing. It sounds like in your case, the Caddy may be there to supplement the heat. You can bring up the house temp with the central furnace, then lower the thermostat and try to maintain with the Caddy. Our LP furnace is set at 68 and it hasn't ran yet this year.

I also forgot, make sure to keep your heat exchanger clean, it does make a difference!

 

[sloeffle]

When I bought my Caddy you could buy one without a blower motor and use the existing furnace fan. From the pics it looks like he has a Caddy Add-On furnace which does not have a blower motor. The silver bezel on the front of his furnace looks different than mine too. Here is a link to the manual @KeithTalent.

It looks like from the manual the fan limit switch ( Honeywell L6064 in the diagram ) would control the fan on your existing furnace. I would think you would be able to fire the gas and wood furnace at the same time due to the blower setup. That is actually kinda nice during really cold days when you need a little extra oomph to get the house up to temp.

I have a thermostat wired into my Caddy also. IMHO, it is worthless. All it does is keep the damper door open until the set point is reached and then closes the damper door.

Edit: I agree with @laynes69 too. 3000 square feet is at the very top end of what the Caddy can heat. Our house is 2,200 sq ft and is insulated okay and it has a hard time keeping up when it gets really ( <10F ) out.

 

[laynes69]

In Canada, the furnace probably has an interlock installed, if so, it keeps the central furnace from firing if the plenum on the wood furnace is at a certain temp. I guess it's for safety, but our old furnace I installed in series and I would fire them both all the time (no interlock). I prefer series myself, however my furnace has it's own blower, so it's in parallel.

If our furnace won't hit the set temperature in a decent amount of time, even if I want it at 74, I'll close the damper at 72 and it will climb (on a reload). Otherwise pumping heat up the chimney, it won't climb to well with the damper open.

 

[KeithTalent]

This is all awesome information, thanks so much. I think you may be right, they are probably meant to work in conjunction with each other, so that I need to blast both at the same time to get the heat up then just use the Caddy to maintain. I am going to try that out tonight to see if it works.

Thanks again for all of the help. Learning a lot!

KT