Single or double wall for basement wood furnace connection?

[mpearce103]

Hello! I've spent countless time trying to find an answer to this to no avail, so decided to post. Thanks in advance for your feedback.

We had two chimneys installed in our new house, one for the main floor fireplace and one to the basement for a future stove/wood furnace. We have the new furnace ready to install but I cannot figure out if it's OK to run single wall pipe from the wood furnace in the basement to the chimney/class A connection in the basement ceiling? The basement/basement ceiling is not finished. The stove pipe will be coming directly out of the back of the furnace, then 90 degrees straight up to the ceiling. Picture attached for reference.

Furnace is a Lamppa Vapor Fire 100.

Thanks! MIKE

 

[begreen]

Single-wall is ok as long as it has 18" clearance from all combustibles, including the red duct tape. I suspect that the supplied barometric damper is designed for single-wall. Be sure the crimped end points down, toward the furnace.

 

[mpearce103]

Single-wall is ok as long as it has 18" clearance from all combustibles, including the red duct tape. I suspect that the supplied barometric damper is designed for single-wall. Be sure the crimped end points down, toward the furnace.

You’re correct, the barometric damper supplied is for single wall. I had a stove installed previously with double wall pipe, but trying to get adapters in order to use the barometric damper with double wall pipe is proving difficult and expensive! Thanks for the reply.

 

[brenndatomu]

You'll be fine with single wall pipe...I used stainless though, just because I got tired of replacing that cheap steel pipe every few years because it rusted out yet again!
If you want to insulate it just get a piece of foil backed chimney liner insulation to wrap the pipe with, seal the seam with foil HVAC tape...it should be fine without insulation though, especially since you are going straight up. Just FYI, there are people on EBAY that sell short pieces of insulation like that.
You'll love the VF!

 

[mpearce103]

Right on. Thanks for the reply! Excited to get it up and running!!

 

[hedge wood]

Just make sure your insurance company and the inspector is good with the single wall. In my area some won't allow single wall any more on wood or 80 percent gas furnaces and hot water heaters.

 

[Wood1Dennis]

Looks just like mine. I have single wall pipe up to the double wall chimney pipe in that piece in the floor joists. Has worked perfectly for 7 heating seasons now.

 

[mpearce103]

Got the VF100 up and running with a “temp” plenum until my HVAC guys can duct it into the existing system. Working awesome so far on a little 4 split fire. Thanks for all the feedback.

 

[brenndatomu]

Got the VF100 up and running with a “temp” plenum until my HVAC guys can duct it into the existing system. Working awesome so far on a little 4 split fire. Thanks for all the feedback. View attachment 310338

Congrats!
Do you have ductwork nearby to tie into? Planning on tying in on the return side too?
When they do the permanent supply plenum, you'll then want to move the low limit switch up high in the plenum.

 

[mpearce103]

Congrats!
Do you have ductwork nearby to tie into? Planning on tying in on the return side too?
When they do the permanent supply plenum, you'll then want to move the low limit switch up high in the plenum.

Yup! Ductwork is very close. And yes, we’ll be tying into the return as well. Understood on the low limit switch… makes sense.

Have to figure out the check flaps that need to be installed… meaning, I know how to make them, but our supply and return go both directions when leaving the furnace. Not sure I’ll be able to isolate the systems properly without some serious re-ducting. Still working this out. 😎

 

[brenndatomu]

Have to figure out the check flaps that need to be installed… meaning, I know how to make them, but our supply and return go both directions when leaving the furnace. Not sure I’ll be able to isolate the systems properly without some serious re-ducting. Still working this out

Hard to understand what you are working with from this side of the screen, but would some powered/spring dampers help? That solved the issue for me, a powered closed/spring open damper...and if this is something you'd consider, also consider going with Belimo damper motors...the best (and no, I don't work for, sell them, or have any affiliation with them, other than as a pleased owner)

 

[mpearce103]

Hard to understand what you are working with from this side of the screen, but would some powered/spring dampers help? That solved the issue for me, a powered closed/spring open damper...and if this is something you'd consider, also consider going with Belimo damper motors...the best (and no, I don't work for, sell them, or have any affiliation with them, other than as a pleased owner)

Absolutely I’d consider that! What calls for them to release/open? Is it tied into the call for heat? Would love more info. Sounds like this may be exactly what I need.

 

[brenndatomu]

Absolutely I’d consider that! What calls for them to release/open? Is it tied into the call for heat? Would love more info. Sounds like this may be exactly what I need.

It can be anything...a thermostat, another appliance kicking on/off, whatever. The dampers are available in 24V or 120V, power open/spring closed, power closed, spring open, or power both ways.
That's yet another thing I like about the Belimo actuators, they can be field converted which direction they operate by spring...that, and they are very low power draw, especially once they reach their powered destination.
This place is great to deal with! https://www.retrozone.com/

 

[mpearce103]

It can be anything...a thermostat, another appliance kicking on/off, whatever. The dampers are available in 24V or 120V, power open/spring closed, power closed, spring open, or power both ways.
That's yet another thing I like about the Belimo actuators, they can be field converted which direction they operate by spring...that, and they are very low power draw, especially once they reach their powered destination.
This place is great to deal with! https://www.retrozone.com/

This is great. Thanks for sharing. I’ve got to draw it up, but I think this will work. Using one of these would allow me to mount it horizontal which fixes a lot of my issues. I’ll keep ya posted.

 

[Wood1Dennis]

Do you already have the backup (gas?) furnace or us that still to be installed? Looks like new construction!

 

[brenndatomu]

This is great. Thanks for sharing. I’ve got to draw it up, but I think this will work. Using one of these would allow me to mount it horizontal which fixes a lot of my issues. I’ll keep ya posted.

You can still do gravity dampers in horizontal ducts, they just have to pivot at the top...and maybe mounted a couple degrees shy of vertical so it tends to lay shut on its own.
I still like power/ spring dampers though...if you do it right you can set it up so the furnace can gravity flow in the event the power fails right when you have a fresh load getting to it's peak temp.

 

[Wood1Dennis]

My system works with no dampers. It is essentially hooked with both gas and wood furnaces in line running on the gas furnace fan. The system works great, but this is what I worry about.

......if you do it right you can set it up so the furnace can gravity flow in the event the power fails right when you have a fresh load getting to it's peak temp.

I would like to do something like this, but it seems a bit excessive to have a powered closed damper taking power all of the time to keep a damper closed just to protect against the risk if an ill timed power outage. I have thought about a manual damper, installed in the cold air return right at the bottom of my wood furnace, but of course that does not help if no one is home in the event of a power outage.

 

[brenndatomu]

I would like to do something like this, but it seems a bit excessive to have a powered closed damper taking power all of the time to keep a damper closed

The Belimo damper motors have VERY low power draw when in the hold position.

I have thought about a manual damper, installed in the cold air return right at the bottom of my wood furnace, but of course that does not help if no one is home in the event of a power outage.

Sounds like a good place for an emergency heat dump door.

 

[usernametaken]

I have two isolation dampers tied into a switch and interlock. Throw the switch one way and its wood furnace. Throw it the other and it's the LP furnace/AC. I also have my thermostats tied into this so that depending on which way the switch is thrown, the same thermostats control either one furnace or the other. This allows me to run a 3 zone system through either furnace on the same 3 thermostats.