Desperately need help with a indoor wood furnace

[practicaldesign]

Hello all.

I have a relative that has a problem with their indoor wood furnace. Here is the link to that furnace.

cast iron wood furnace | Enterprise Fawcett

Now about three years ago the furnace started burning a-lot of wood and giving little to no heat.

Both barometric dampeners are new and calibrated. Pipes are new as well.

The chimney is 13" x 9" I.D. flue roughly 40 foot tall double brick thick.

The chimney is very clean and so are the heat exchangers of the furnace itself.

There are no cracks or holes in the firebox or heat exchanger.

The problems are:

1: Sometimes there is too much draft that you need a propane torch to light the fire and that's with the dampeners open.

2: Many times the draft just stops almost all together and the fire goes out.

3: Many times the firebox gets so hot i need gloves to grab the door handle, however very little heat is getting into the plenum.
so little heat that the fan control thermostat "turn on" is down below 100f when it was originally at 150f.

4: Many times one has to use green firewood over the dry wood to get any kind of heat.

5: The enterprise furnace often will have more than enough draft but as soon as the fire produces a bit of smoke the fire suddenly back
drafts, and the fire goes out even if you have a blower injecting air.

6: I tested the chimney with my camp furnace (45 gallon drum) with the same stove pipes and dampeners as the enterprise furnace and it
never failed to work.


The problems are strange as there is no middle ground, and the fact that the heat is not getting into the plenum is the oddest
problem and there are no obstructions and everything is pretty much spotless yet at times you can't even grab the loading door
handle because it's so hot.

The firebox is still quite thick and so is the heat exchanger, it's built like a tank. However i can't figure out what would cause
such drastic changes or differences.

BTW the oil furnace is connected to the same exhaust pipes as the wood furnace and the oil furnace has it's own dampener as well
and it works very well.

Yes i tried pre-heating the wood furnace with some paper and bark. No difference it flares up for about 10 seconds then back
drafts for forwards drafts in pulses and you can see it happening with both dampeners flapping in sync at about 1-2 flapings per second which can't be natural. I did seal off both barometric dampeners dampeners to see if a straight uncontrolled exhaust would help and nothing changed.

I've installed a blower on the front air intake, same effect either it works to feed the fire or it puts out the fire.

I've opened the windows in the home to see if it was that but no change.

Any ideas?

 

[Dan_IN_MN]

Have you cleaned the heat exchanger? I'm wondering if there is ash built up in there insulating it so heat can't escape.

Have you contacted the manufacturer?

 

[brenndatomu]

I assume that it did work good at some point in the past?
You say the BDRs are new and calibrated, with a manometer? To what setting?
I know that two appliances on one flue is not the preferred setup, I wonder if two BDRs on one flue could be causing trouble. Ever try holding the oil one closed to see if the wood side one would work properly? They shouldn't flap around wildly unless it's windy.
As far as not getting heat into the house, I'm thinking like manyhobies, plugged up heat exchanger, heck, that could be the whole problem.
I don't understand how burning green wood is helping you make more heat?!? Wet wood equals no heat and lots of creosote in your heat exchanger, flue pipe, and chimney.
Ever have the chimney looked at professionally?
By the way, which furnace to you have?

 

[cantoo]

practicaldesign, I have an older stove like that but have no idea what could be wrong with your setup. dave_dj1 has an old one too, maybe he can help you? Try a search using his name.

 

[stihly dan]

The draft would have to be the heat exchanger, also if the door is so hot and the fan is running and moving air, this also would be clogged heat exchanger. Heat is there, but the soot is creating insulation. Be careful not to ruin the steal with to high of heat temps, if it's not already ruined. Clean the inside of the heat exchanger.

 

[dave_dj1]

I'm not familiar with that model but I'm wondering if it has something to do with the plenum? Maybe it's plugged.
On my model there is a little clean out cover under the stovepipe on the rear, remove a couple of screws and you can see into the expansion chamber (for lack of a better term).
That could be plugged up with something. Or as others have said, the air chamber itself which would require removing the plenum to clean it.

 

[practicaldesign]

Thanks.

1: Yes the heat exchanger(s) are completely clean brushed, buffed inside and out and can't get any cleaner.

2: The plenum is clean and no blockages anywhere.

3: The dampeners were calibrated with the meter multiple times by different repairmen.

4: The green wood is to slow the rapid flame and it does not leave that much creosote. It's one piece of green wood split into 4 and placed over the dry wood and yes it gives a longer more stable heat which does fill the plenum better.

I wasn't joking when i said it was weird.

The furnace has been disassembled in its entirety and the exchangers don't get all that hot either.

 

[practicaldesign]

I'm not familiar with that model but I'm wondering if it has something to do with the plenum? Maybe it's plugged.
On my model there is a little clean out cover under the stovepipe on the rear, remove a couple of screws and you can see into the expansion chamber (for lack of a better term).
That could be plugged up with something. Or as others have said, the air chamber itself which would require removing the plenum to clean it.

Hi and thanks. No there is no clean out at the back on this model.

Here is how it's setup.

rounded top firebox

From there it splits into a Y that connects to two pipes (part of the exchanger) that stretch forward to the front where the is a second Y that goes up to a third larger tube that stretches out the back and the exhaust.

The three exchanger tubes have clean out plates in the front about 2 feet above the firebox door. You unscrew each door plate and run a furnace brush through each tube into the stove and the straight one out to the exhaust pipe and the chimney . The Y's are also scrubbed , the end plates or caps are sealed back on with furnace cement.

 

[practicaldesign]

Have you cleaned the heat exchanger? I'm wondering if there is ash built up in there insulating it so heat can't escape.

Have you contacted the manufacturer?

Yes i have contacted Enterprise faucet and they never answer email, faxes even for parts orders. I wouldn't be asking here if i hadn't tried other avenues.

 

[laynes69]

A 9x13 flue at 40' will cause unstable draft. It won't draft at first until it's warm, then once hot from a fire it will overdraft heavily. Once the damper on the furnace closes, or the fire dies down, there's not enough heat to maintain draft. On top of this, your sharing a oil furnace on the flue with duel barometric dampers. In reality, your wood furnace should be on a dedicated flue, with an insulated liner (especially with the height). A flue liner will stabilize draft on both high and low fire. Instead of guessing on draft, a cheap 35 dollar manometer will verify draft speeds. Having an on temp of 100 also does no good for the furnace, it needs to build some heat before the fan kicks in. It sounds silly, bit make sure both supply and return registers are open, and if any air filters, check they are clean. Either there's too little draft allowing not enough heat or too much, which pulls heat out of the furnace before it has a chance to exchange. Green wood compounds the problem, yeah it might burn longer but total output will suffer, water doesn't burn well. I'm betting it's unstable draft. If there's a cleanout cover, make sure it's sealed.

 

[practicaldesign]

I assume that it did work good at some point in the past?
You say the BDRs are new and calibrated, with a manometer? To what setting?
I know that two appliances on one flue is not the preferred setup, I wonder if two BDRs on one flue could be causing trouble. Ever try holding the oil one closed to see if the wood side one would work properly? They shouldn't flap around wildly unless it's windy.
As far as not getting heat into the house, I'm thinking like manyhobies, plugged up heat exchanger, heck, that could be the whole problem.
I don't understand how burning green wood is helping you make more heat?!? Wet wood equals no heat and lots of creosote in your heat exchanger, flue pipe, and chimney.
Ever have the chimney looked at professionally?
By the way, which furnace to you have?

This was covered in my initial posting.

I sealed either and both dampeners to see what it would do.

 

[practicaldesign]

The only thing i see is that it's one of the Y's but there is nothing wrong with them.

 

[dave_dj1]

WOW! It is wierd.
How is the door gasket? Looking at the owners manual on their site it looks as though you have to assemble the unit upon delivery. That includes some furnace cement in certain joints. Is it possible these joints have failed allowing air to draw in? How dry is the dry wood? I'm just throwing stuff out there, I know it would drive me crazy until I figured it out.
When I first got mine I called Enterprise Fawcett, they were very nice on the phone.

One other thing that comes to mind, how about outside, any recent tree removals or changes to the general location, IE dormers added etc. etc.?
Good luck,
dave

I wonder if the bottom could have a rust hole in it?

 

[stihly dan]

Fill it with wood, chock full. You may just not be putting enough wood in. If my furnace is cold, it takes about an hour to heat up the whole unit before it blows heat. Once its hot you will get heat soon after loading wood. Theres probably 500 lbs of mass that has to get hot before you can get heat on yours.

 

[practicaldesign]

WOW! It is wierd.
How is the door gasket? Looking at the owners manual on their site it looks as though you have to assemble the unit upon delivery. That includes some furnace cement in certain joints. Is it possible these joints have failed allowing air to draw in? How dry is the dry wood? I'm just throwing stuff out there, I know it would drive me crazy until I figured it out.
When I first got mine I called Enterprise Fawcett, they were very nice on the phone.

One other thing that comes to mind, how about outside, any recent tree removals or changes to the general location, IE dormers added etc. etc.?
Good luck,
dave

Yes like i asked the person at woodheat.com. About 3 years ago they did a huge clear cut about 500 feet form my relatives place. However i am reticent to that causing that much of a change to a furnace. It certainly got colder that i will admit to.

Brand new door gasket, and all cemented sections are sealed.

One thing i did notice recently is that one side of the furnace (left side has more draft and it's pulling the flame to the left) , and often the wood on the left hand side won't burn as well.

 

[practicaldesign]

Fill it with wood, chock full. You may just not be putting enough wood in. If my furnace is cold, it takes about an hour to heat up the whole unit before it blows heat. Once its hot you will get heat soon after loading wood. Theres probably 500 lbs of mass that has to get hot before you can get heat on yours.

24" pieces of very dry wood filled to the top and the door gets so hot that the paint on the heat shield above the door burns off, and i can put my hand on the plenum and hold it there and not get uncomfortable.

 

[stihly dan]

how hot is the flue pipe?

 

[practicaldesign]

how hot is the flue pipe?

Will check again. However sometimes i have seen flames through the dampener.

 

[practicaldesign]

Before any one asks i put dry tamarak wood in the furnace. That wood burns so hot that it warps furnaces , so i have tested the wood dryness theories to death.

 

[stihly dan]

If you turn the fan on do you get air out the regesters, is the return sucking? Heat rises, so if the fire box is that hot, where is the heat going? Up the chimney? Is there a heat exchanger bypass?