Mojappa's Drolet Heatpack Adventure

[Mojappa]

Hey guys, figure there's no time like the present to start trying to get what help/advice I can regarding the install of my wood furnace. I plan to take some measurements and draw up a rough sketch of the layout of my house soon to better explain what I have to work with and the best options to accomplish what I'm trying to do.

Quick history: bought my house in June 2016, had chimney relined the following February and started trying to use the Fisher Papa Bear in the basement. Didn't use it too long as it was a pretty mild winter so little knowledge/experience was gained. Fired it up again this past Nov. and began my battle of trying to get heat out of the basement with little success. We ended up setting up the air mattress in the basement during the really cold weeks in Jan., nearly ran out of wood and decided to shut it down and pay electric bills for the remainder of winter while researching wood furnaces. Basement is partially finished but not enough to really improve heating.

a few quick questions to start with. I want to run a main duct from it into the trunk line that runs across the basement ceiling but going all the way to the air handler from the furnace is gonna be quite a long run. I'm thinking I can run a duct into the end of the trunk line at the end opposite of the air handler and install a one way damper or something similar to stop the air from going all the way down into the air handler itself. I'm just not sure if the fan on the Heatpack will be enough to push heat all the way through the ducts. I know this will be easier to "diagnose" when I get measurements drawn up. If so is it possible to build the plenum with one ot two 8" ducts coming off like most regular furnaces have? the plenum kit it came with has 10 6" ducts coming off it in all directions. my other thought if tapping into the end of the trunk line wont work is to just run separate ducts from the furnace and cut new registers. I also have a weird shaped duct running up to the loft and the two registers up there. If I go with separate heating ducts is it possible to tie into that duct? it would probably be 30' run just to get over to where that duct starts going up through the house. I'll also post pics as I go to help clarify what I've got to work with. I'm determined that we aren't gonna be wearing hoodies and extra pants to stay comfy in the house next winter. Thanks in advance for any help I may receive.

 

[brenndatomu]

Will wait for pics and or sketches, but just know that the shorter you can keep your runs, the better...I ran separate ducts at my sisters place...worked out pretty well. That allows you to have the CTC (clearance to combustibles) on the ducts that you are supposed to with a wood furnace...and fossil fuel furnaces usually don't have. Also allows you to put some rise on the runs so you can get some gravity airflow during a power outage...

 

[Mojappa]

Rough sketch for the time being along with a pic of the house for size reference. The highlighted parts are the supply runs from the air handler. The trunk like running down the center is decent sized rectangular “tubing”. Like I said earlier, I think it unrealistic to run to the plenum of the air handler but thought maybe I could come into the trunk run from the opposite end and add a damper to stop the heat from going all the way to the handler. Small change with the drawing, seems I reversed the return and supply trunk ducts, the supply is closest to the furnace. I’ll post a pic of the trunk lines too, there’s also a main support beam running down the center of the basement between the furnace and the trunk runs, I’d either have to go over or under that to get to the supply.

 

[Mojappa]

Took a few quick measurements before work today. It’s about 6’ from the flue over to the closest wall (to the left in my drawing) and about 12’ from that corner out to the trunk run. That would be less than a 20’ run to get over to the trunk, just not sure if the furnace has the oomph to push the air all the way upstairs after getting to the trunk.

 

[brenndatomu]

just not sure if the furnace has the oomph to push the air all the way upstairs after getting to the trunk.

I don't think "enough oomph" will be an issue...the problem is that air is not the best way to transfer heat (water is much better) and on long runs like that you lose temp...I think this will work for you but you are going to need to insulate the supply ducts well...and I'd still run separate ducts for the wood furnace if at all possible...that will give you the best possible outcome IMO.

 

[Mojappa]

Thanks for the input. I was hopeful that using the existing ducts would work cause it would be infinitely cheaper to just run to the supply line and put a damper before the handler. I would still have to patch into the main duct that runs up to the loft where the bedroom is, I don’t think there’s room to run a separate duct all the way up there.

Do you think I could tap into the return that’s near the stove to put a return on the furnace?

 

[brenndatomu]

It shouldn't cost that much to run some 6-8" round ducts...that stuff is pretty inexpensive really.
I think tying into to existing ducts for return air should be fine.

 

[maple1]

What is hooked up to this ductwork now?

 

[Mojappa]

Electric ac/heat pump

 

[maple1]

Electric ac/heat pump

See post 2 : That allows you to have the CTC (clearance to combustibles) on the ducts that you are supposed to with a wood furnace.

Don't know what your exact existing duct situation is, but wood burners usually have different requirements. CTC, and depending what you have now, maybe also material. Just something to make sure of before you commit to anything.

 

[STIHLY DAN]

NO! NO! and NO!. Everything is wrong. Worst, that is duct board! absolutely NOT, Duct mains are tapered so NO again. Return has NO CTC! NO! NO! Run new ductwork or dont use a wood furnace! Sorry, it is what it is.

 

[brenndatomu]

NO! NO! and NO!. Everything is wrong. Worst, that is duct board! absolutely NOT, Duct mains are tapered so NO again. Return has NO CTC! NO! NO! Run new ductwork or dont use a wood furnace! Sorry, it is what it is.

Since when do you need to have CTC on your return air?

 

[STIHLY DAN]

He asked if he could tap into the return? post #6

 

[brenndatomu]

He asked if he could tap into the return? post #6

My understanding of post 6 was the he would be tapping into the return air...for return air...correct me if I'm wrong @Mojappa

 

[Mojappa]

My understanding of post 6 was the he would be tapping into the return air...for return air...correct me if I'm wrong @Mojappa

Correct. My girlfriend would kill for a house so warm that the return air temps were a CTC concern

As for the supply run, fear not Brenndatumo, after like the third reply it became pretty evident that running separate ducts from the furnace was about my only option. Though I think only the return is duct board, the supply trunk seems to be something else (could be wrong), but either way it’ll be way less complicated and safer to be on its own.

Speaking of the return, would tapping into the existing one suffice or would that introduce weird behavior for A/C return air or when the heat pump kicks on if the furnace dies down?

 

[JMihevic]

Electric ac/heat pump

I haven't looked into the detail of your installation, but I have a heat pump/AC just like you and have been very happy with my wood boiler add on. I put it in 38 years ago and it works as good as the day I put it in. Here's a link to my post.

https://hearth.com/talk/threads/new-member-long-time-owner-of-1980-tarm-boiler.167275/

John M.

 

[Mojappa]

Made some progress and finally got to fire it up thanks to the help of a few members here. No ducting hooked up yet but thankfully it is working well to reduce the load on my electric heat and I’m getting to learn the ins and outs about using this thing. Tax return should be in the bank tomorrow (one thing I never procrastinate on lol) so if I can find someone I trust to help me I could have the ducting installed by the end of Feb.

After this cold front is gone I’m gonna install the manometer but I’m pretty sure my chimney is too short and producing a fairly weak draft. If I can I’ll try to shove a cheap piece of stovepipe in there as a temporary extension to see if it changes anything. Right now even with wood measuring around 16-18% the smoke coming from the chimney while secondaries are active is still a bit thick and brownish. Looked that way last year with the fisher but was thicker and lingered way longer than it does now. Didn’t have a moisture meter last year so assumed it was wet wood more so than the draft.

So far ive only got a handful of loads through it but it’s pretty easy to get 8hrs out of it, probably should be giving it a bit more time at the end to break down the last coals a bit more, tends to be decent sized chunks glowing in the back when it’s convenient for me to reload

 

[Getwidit]

How ru making out with the heat pack I have mine 75% set up. Cant wait to get it fired.

 

[Mrpelletburner]

So far ive only got a handful of loads through it but it’s pretty easy to get 8hrs out of it, probably should be giving it a bit more time at the end to break down the last coals a bit more, tends to be decent sized chunks glowing in the back when it’s convenient for me to reload

I know you posted this last year... but when you are back in the swing of things, can you snap a photo of the firebox at the 8hr marker?

 

[JRHAWK9]

I know you posted this last year... but when you are back in the swing of things, can you snap a photo of the firebox at the 8hr marker?

Also need to know what the loading was. A load of 15lbs after 8 hours looks a LOT different than say a 70lb load after 8 hours.

 

[Mojappa]

Finally got some progress in the last week. Got three of my runs done, two more will be done by this weekend. At work now, just wanted to make a quick update so y’all know I didn’t burn my house down lol. I’ll make a more in depth post and address questions after work this evening.

 

[Mojappa]

Also need to know what the loading was. A load of 15lbs after 8 hours looks a LOT different than say a 70lb load after 8 hours.

I generally do before and after pics do a load pic will be included. Not a weight though cause I don’t have a scale.

 

[Mojappa]

An old friend came out and helped me run the first three ducts. I had cut the register holes and put the boots in place already, just needed a knowledgeable helping hand (turns out he does HVAC now for work so that was a blessing) to get them piped. Definitely not gonna win any style awards with my setup but it functions and hopefully has enough rise for some convection.

Still three more to run and one of them is posing quite a bit of challenges just trying to plan out so I may just run it most of the way I need it to go and then let it dump into the basement till I can figure out how I can run it up to the loft/bedroom. That’s if I even need it up there, I’ll figure out more after I get the other two ducts run since they heat the rooms below the loft.
First couple of burns in it definitely seem promising for its ability to heat our fairly small house, but at the end of the burn all my combined inefficiencies upstairs make it cool back off fairly quickly. It’s not cold enough yet to want to burn full time, still in the 50’s during the days and tonight might dip to 40. Tomorrow night is supposed to get into the low 30’s so that might be the next chance to burn and get an 8hr photo for mrpelletburner. Still gotta put the good ol’ plastic film over the windows (that’s the next project, updating the windows) and that should help a bit with the cooling. Not going to hesitate too long on getting the variable speed controller mod done as that should also help quell the cooling some. One step at at a time, but the first step was getting the heat out of the basement and into the house so glad that one’s mostly taken care of.

 

[Mrpelletburner]

If you are ok with blocking the light entering the window, you could wedge 1” hard rigid foam insulation board on the inside of the window frame.

 

[brenndatomu]

If you are ok with blocking the light entering the window, you could wedge 1” hard rigid foam insulation board on the inside of the window frame.

And you could have an artist paint a nice mountain view on it then too!