why do i keep having explosions!!!???

[Felman]

The stove & chimney are full of uncombusted gas & when it combusts it explodes. Simple fix may be to open the stove door & let the gas evacuate before reigniting?

 

[aaronmach1]

Looking at the pictures you posted in the other thread:
I'm wondering if you have an air return into the room where that stove is? Is the door to the basement kept open?

I do not have an air return. The basement stairway at the top has a door out to the garage and a door that goes into the kitchen. Neither one stays open. Although sometimes like when the gas furnace runs etc, i can feel a slight bit of cold air being pulled in through the door seal, on the door that goes to the garage.

 

[aaronmach1]

The stove & chimney are full of uncombusted gas & when it combusts it explodes. Simple fix may be to open the stove door & let the gas evacuate before reigniting?

Looks like creosote to me. lots of it, maybe from last nights overnight slow burn?

 

[aaronmach1]

Why did you put in a 6x10" liner? Your furnace calls for a 6" flue exhaust which is around 28 sq.in. Your liner is 60 sq.in which is a little more than double the size needed. The larger the flue, the longer it takes to heat the chimney. This will cause a sluggish draft and can cause creosote. With a chimney liner, bigger isn't better. You should have installed a 6" flue to match the furnace. The liner is safer than the original, but it's size doesn't help anything. Also looking at your flue pipe off the furnace if your not running a baro, you have leakage in the pipe.

I have NO idea! Did i screw up? The chimney guy ordered it for me. The original clay tile flue is 8x12 inch. So he just said he will order me what i need and i picked it up. Its actual size is just under 6"x just under 10".

 

[aaronmach1]

also this flapper adjuster has four settings from high to low on the load door. The fire really roars with it open. I usually keep it closed. Any opinions on using this? took the cover off in 2 pics so you can see it open and closed.

 

[Chris-PA]

I do not have an air return. The basement stairway at the top has a door out to the garage and a door that goes into the kitchen. Neither one stays open. Although sometimes like when the gas furnace runs etc, i can feel a slight bit of cold air being pulled in through the door seal, on the door that goes to the garage.

The gas furnace has a return, but it may be into the ductwork, not into the basement room itself. I cannot tell from the pictures.

If there is no return into the basement room area, then when the blower on the furnace runs it has no where to get return air from. That means it's trying to pull air back down your flue and pump it into the rest of your house - depending on how well sealed your house is, that may be mostly a closed cavity. More than likely there are ways for air to get out of you house (kitchen or bathroom vents, etc.), so your blower is fighting the draw of the flue.

 

[aaronmach1]

The gas furnace has a return, but it may be into the ductwork, not into the basement room itself. I cannot tell from the pictures.

If there is no return into the basement room area, then when the blower on the furnace runs it has no where to get return air from. That means it's trying to pull air back down your flue and pump it into the rest of your house - depending on how well sealed your house is, that may be mostly a closed cavity. More than likely there are ways for air to get out of you house (kitchen or bathroom vents, etc.), so your blower is fighting the draw of the flue.

yes the gas furnace has cold air retun ducts. vents in all 3 bedrooms and one in the livingroom.

 

[Chris-PA]

yes the gas furnace has cold air retun ducts. vents in all 3 bedrooms and one in the livingroom.

But those returns don't go into the basement room space, they go into the return ductwork, so this seems like a significant problem. The room where the wood furnace is has no opening to the rest of the house. When the blower is on, where can it draw air from? The only place is back down the flue. Now if it has no place to push that air, then maybe it doesn't matter (the blower would just be ineffective), but likely it does have some leaks to push air out of your house. So it is fighting the draw of the flue.

The blower on the wood furnace was intended to circulate air around your house - why not plumb that open return on the stove into the return duct from your gas system? Otherwise, you need to provide a way for air to move into the basement room, such as leaving the door to your kitchen open or putting a vent in it.

I'm guessing way too much from your pictures - I think you've got a significant problem with that install and should have it looked at in person by someone knowledgeable.

 

[Chris-PA]

Well if that's the case can't he just put in an 'outdoor air supply' and solve the problem?

Well, no - not if the ducting is really like it seems. But I sense there is some history here I'm not aware of, and I'd prefer to stay out of old feuds!

 

[laynes69]

I have NO idea! Did i screw up? The chimney guy ordered it for me. The original clay tile flue is 8x12 inch. So he just said he will order me what i need and i picked it up. Its actual size is just under 6"x just under 10".

It's better than a cracked flue. It will just take longer to heat up and cool faster than a 6" flue. The warmer those gasses, the better the draft. Also keeping the flue gasses hotter will help keep creosote down.

 

[laynes69]

It's not, which I explained in a different thread why it should be for safety.

 

[aaronmach1]

It sounds like you've hit on a major problem with the install but I don't think it's as simple as attaching the return duct on the wood furnace to the return duct on the main furnace. There would need to be some way of keeping the pressurized air in the hot air duct work from flowing back through the heat exchanger in the main furnace and meeting up with the negative pressure in the cold air return. An option may be to run the cold air return duct from the wood furnace up to the first floor and intstall it's own seperate cold air return grate.

As the ductwork is now the wood furnace blower is probably blowing warm air through the hot air duct and some of that hot air is going through the main furnace heat exchanger and flowing into the upstairs via the cold air return system. This is not really a problem if the wood furnace had it's own cold air return system. If the main furnace chimney is still drafting there may be a constant stand by heat loss through the main furnace heat exchanger and up the furnace chimney.

i just checked and all the cold air return lines for the gas furnace are cool. All of the heat ducts and plenum are hot. I do not think any hot air is running downward in the plenum then back up through the cold air return ducts. It would have to flow up out of the stove angle up to the plenum then go down through the bottom of the furnace then back up and into the cold air retun ductwork.

And, as for the make up air that some are saying i may need isnt it possible the wood furnace can pull makeup air back down through the gas furnace flue and through the furnace?

 

[aaronmach1]

And, as for the make up air that some are saying i may need isnt it possible the wood furnace can pull makeup air back down through the gas furnace flue and through the furnace?

 

[Chris-PA]

i just checked and all the cold air return lines for the gas furnace are cool. All of the heat ducts and plenum are hot. I do not think any hot air is running downward in the plenum then back up through the cold air return ducts. It would have to flow up out of the stove angle up to the plenum then go down through the bottom of the furnace then back up and into the cold air retun ductwork.

And, as for the make up air that some are saying i may need isnt it possible the wood furnace can pull makeup air back down through the gas furnace flue and through the furnace?

This issue would only effect how well the heat from the unit is distributed throughout the house, not how it burns.

 

[aaronmach1]

Plus it would have to go through the squirrel cage fan in the furnace. Sounds good than no heated air it moving that way. I doubt your furnace has a damper that would prevent that flow.


I you leave the door from the first floor to the basement open is will act as a cold air return to the basement and if this has been why your wood furnace has been back puffing......then the mild 'boom' you mentioned and the back puffing should stop.

If the mild boom and backpuffing still happens it may be that you are adding a bit much of fresh fuel onto a hot bed of coals and then choking the wood furnace back to soon.

As someone else earlier mentioned.......if your house it to tight to allow enough air to enter for your wood furnace....to test it all you need to do is open an outside window a few inches and see if the back puffing stops.

Woodheatwarrior was very observant to notice no cold air return on your set up.

Well if i open the stairway door to the kitchen then the 1st floor gets that burned wood smell. I would like to not have that smell in the whole house. Also tonight i started a fresh fire after no burn all day and i havnt had any explosions. It has to be the adding of new wood to hot coals then i shut it down to 2 turns on the ash damper and 1/2 close the flue damper.

 

[aaronmach1]

im trying the load door flapper damper today but i just cant figure it out, sometimes if i put it on low open ill come back and its closed itself or other times i set it on low open and i come back and its on high open.

 

[aaronmach1]

It may have a bi-metal coil that senses heat from the furnace and closes down as the furnace gets hot and opens up when the furnace cools.

hmm ok, i posted pics of it on page 3 or 4. I can really get a fire roaring with it open on high.

 

[aaronmach1]

Yes, that is a bi-metal coil.

If you think you've solved the backpuffing problem by how you build fires...........you still have the lack of a cold air return problem to solve. It may be as simple as a grate cut into the basement doorway.

well like i said there is a small landing and two doors at top of stairs. One door to kitchen and one to garage. I just held a cob web fuzzy thing up all around the garage entry door seal and there is is a small draft being pulled in through that. that may be feeding the fire.

 

[aaronmach1]

if i just simply run a pipe from the gas furnace cold air return ductwork to the woodfurnace blower it would be like a big circle of air. Air goes up throught heat ductwork and then back down the cold air ductwork through the woodfurnace then starts cycle all over again. Is that what i need? Just run a 4 inch pipe off the existing cold air returns?

 

[aaronmach1]

It may be that you can tie the cold air return off of the wood furnace into the cold air return of the main furnace. You need to get a HVAC professional on site to see what can be safely and by code. It's hard to believe your setup passed any kind of inspection without a cold air return for the wood furnace.

i didnt have an inspection. Just a simple questionaire for insurance and then took them a couple pics plus measurements and they said ok.