Tested !!!!

[Whitespider]

Sunday was a nice day; I took the plastic and storms off some windows, installed the screens… about half the house. Yesterday was cool, windy, rainy, no sun and in the low 40’s. When I got home from work the house was down to 64[sup]o[/sup]. Now normally, after all the warm weather, I’d be thinkin’, “crap, gonna haf’ta start a fire in the furnace”… But I’ve been itchin’ to give the new furnace build a test so I’m thinkin’, “COOL!”

Anyway, even though it wasn’t zero outside, I figured with the wind blowing, storm windows off half the house and screens on the doors it would be a valid test. Ooooh yeah, it puts out some serious heat… the air pumping from the registers is much warmer than the old dragon produced. It took about an hour before everything came up to full temp, but when it did… About 4 hours after I fired it up all six rooms in the house were a comfortable 70[sup]o[/sup].

I do need to make a couple of small tweaks though. I put the temp sensor that turns on the blower in the heat pipe coming off the plenum, and this morning when the fire had burned down to a (nice) bed of coals the blower was cycling on and off every few seconds. I need to move the sensor somewhere else… maybe on the stack where temp fluctuations won’t be an issue. The other thing is (maybe) I’ll need to change the blower speed, kick it up one notch to take advantage of the extra heat being produced.

I’m glad I installed the flue damper… I had the stove control set on the lowest setting last night and it was hot… damn hot. Might be I have a bit too much draft that will only get worse as temperatures get colder, but like anything else, it will take a bit of “playin’-‘round” to find the best setting(s). There’s also a ton of heat escaping through that “glass” door; it’d be nice to figure a way to direct that into the blower system… especially when it get really cold outside. Still, all things considered, I’m pretty darn pleased… and it ain’t all bad having a little heat in the basement when I go down to shower in the morning.

 

[cnice_37]

Nice! I wish I had forced hot air I would be a wood furnace man in a heartbeat.

 

[dave_dj1]

Glad to see it is working well for you! On my wood furnace the fan limit switch is mounted in the front upper left hand corner (it came from the factory that way).
Do you have a fan limit switch or an electronic thing to turn the blower on? I don't know anything about the new fangled stuff :msp_confused:

 

[Whitespider]

I just used a "snap" switch that closes (blower on) at 110[sup]o[/sup] and opens (blower off) at 90[sup]o[/sup], mounted inside the heat duct coming off the plenum. I use the gas furnace blower to push air through the wood furnace. When the fire burns down to a bed of coals the air moving through cools enough to open the switch, but in just a few seconds after that the air inside the plenum (without movement) heats up enough to close it... then open... then close. I'll make a box to mount on the stack, install the switch in the box, and that way it won't be subject to air flow. The blower will run from stack temp, and I should be able to regulate it by adding (or plugging) vent holes to the mount box as needed.

 

[laynes69]

A cheap honeywell limit/control would be the thing to have. Adjustable from 75-250 degrees. Just place it in the duct that supplies the heated air to the system. I've seen them on eBay for cheap, as well as other sources. The larger the gap, the longer the blower will run. I think it would be easier than dealing with flue temps, and easier to tweak.

 

[Dan_IN_MN]

I just used a "snap" switch that closes (blower on) at 110[sup]o[/sup] and opens (blower off) at 90[sup]o[/sup], mounted inside the heat duct coming off the plenum. I use the gas furnace blower to push air through the wood furnace. When the fire burns down to a bed of coals the air moving through cools enough to open the switch, but in just a few seconds after that the air inside the plenum (without movement) heats up enough to close it... then open... then close. I'll make a box to mount on the stack, install the switch in the box, and that way it won't be subject to air flow. The blower will run from stack temp, and I should be able to regulate it by adding (or plugging) vent holes to the mount box as needed.

I'd like to see how you have the duct work set up to use the gas furnace to push the air through your wood furnace. Currently, I'm using my LP blower to draw heat off of the wood furnace....it works....but not as efficient.... Lots of return cold air mixing with the hot air....gives warm air out the heat vents.

Great job on re-purposing an old stove!

I actually was wondering if you'd fire that thing up with the lower temps we've been getting.

 

[WidowMaker]

Sunday was a nice day; I took the plastic and storms off some windows, installed the screens… about half the house. Yesterday was cool, windy, rainy, no sun and in the low 40’s. When I got home from work the house was down to 64[sup]o[/sup]. Now normally, after all the warm weather, I’d be thinkin’, “crap, gonna haf’ta start a fire in the furnace”… But I’ve been itchin’ to give the new furnace build a test so I’m thinkin’, “COOL!”

Anyway, even though it wasn’t zero outside, I figured with the wind blowing, storm windows off half the house and screens on the doors it would be a valid test. Ooooh yeah, it puts out some serious heat… the air pumping from the registers is much warmer than the old dragon produced. It took about an hour before everything came up to full temp, but when it did… About 4 hours after I fired it up all six rooms in the house were a comfortable 70[sup]o[/sup].

I do need to make a couple of small tweaks though. I put the temp sensor that turns on the blower in the heat pipe coming off the plenum, and this morning when the fire had burned down to a (nice) bed of coals the blower was cycling on and off every few seconds. I need to move the sensor somewhere else… maybe on the stack where temp fluctuations won’t be an issue. The other thing is (maybe) I’ll need to change the blower speed, kick it up one notch to take advantage of the extra heat being produced.

I’m glad I installed the flue damper… I had the stove control set on the lowest setting last night and it was hot… damn hot. Might be I have a bit too much draft that will only get worse as temperatures get colder, but like anything else, it will take a bit of “playin’-‘round” to find the best setting(s). There’s also a ton of heat escaping through that “glass” door; it’d be nice to figure a way to direct that into the blower system… especially when it get really cold outside. Still, all things considered, I’m pretty darn pleased… and it ain’t all bad having a little heat in the basement when I go down to shower in the morning.

===

I have often thought of doing someting like that. Wonder what the county bldg dept and insurance company position on such a project would be????

 

[stihly dan]

Yes a honeywell 6031 would work nicely. Maybe set at 150 90. You need a wider temp margin. good luck.

 

[Dan_IN_MN]

===

I have often thought of doing someting like that. Wonder what the county bldg dept and insurance company position on such a project would be????

They'd probably be okay with the stove in it's stock form. However, thinking outside the box might not be their first skill.

When we were getting advisement for fitting our little girl in a car seat, they suggested using the floating noodles underneath the seat if the car seat didn't allow the seat to sit in the proper position. They also suggested using rolled up towels or something similar inside the seat to support the babies head on the sides. Well...I had found a device that supported her head (upside down U shape) really well. It was held in place by thin fabric behind the baby (and I believe the shoulder straps went though it just to keep it in position). They said. "We can't recommend this because it puts something behind the baby." After all of the suggested modifications, which in my opinion were very "rigged", they couldn't think outside their box and see the function in a product that would stay in place and keep her head from flopping to the side. Can you believe this? A piece of cloth probably not more than.030 thick getting in their way because they were probably told...."do not put anything behind the baby.....on the sides is fine"

I still shake my head.....

 

[Whitespider]

The problem with most (gas or oil) furnace limit/controls is they have a “high limit” that shuts the furnace down in the event of overheating, which is not what I would want. The last thing I’d want to happen is have the blower shut off because the plenum temperature went above the “high limit” of the controller. Yeah, some of the Honeywell controllers would work OK, but they ain’t what I’d call “cheap”… my “snap” switch cost me all of $8.oo.

I built a small box last night that puts the switch about 3-inches off the flue pipe just above the plenum… when the inside of the box reaches 110[sup]o[/sup] (using the outside wall temperature of the flue) the blower will start, when it drops to 90[sup]o[/sup] it will stop. Because the flue isn’t subject to “cyclic” temperatures below 100[sup]o[/sup] during operation (it just rises to peak and falls to ambient as the fire dies) it should keep the blower running steady as long as there would be heat available… and once it stops, it shouldn’t start again until more fuel is added to the firebox. Of course, now it’s warmed up again so I’ll have to wait to test it…

In the picture you can see the patch I put on the heat duct where I had the switch mounted before.

 

[dave_dj1]

While that sounds good in theory, what will happen if there are just hot coals and the air in the plenum gets up to temp and the flue doesn't? I would go with the fan limit switch in the plenum, they won't shut down until the air in there does. Of course I could be all wrong but I would hate to see you have a problem.
dave

 

[Whitespider]

Dave...
The plenum air cannot get any hotter than the stove steel...
The stove steel cannot get any hotter than the air (and firebrick) inside the firebox...
The air inside the firebox is exiting through the flue...
Likely the flue will be the hottest part of the whole system.

 

[Hedgerow]

Dave...
The plenum air cannot get any hotter than the stove steel...
The stove steel cannot get any hotter than the air (and firebrick) inside the firebox...
The air inside the firebox is exiting through the flue...
Likely the flue will be the hottest part of the whole system.

I see your theory... It should work... Unfortunately you're limited to the 90-110 degree range, but for $8, it sure is worth some tweaking time... Let us know how it works the next cool snap we get.
If we get one...

 

[laynes69]

On a woodfurnace, the limit is only wired to the damper or forced draft. If that temp is hit, the damper closes but the distribution fan will still run to cool the unit. The only thing that may pose a problem with the sensor at the flue is with a constant fan on, the stove may never hit it's temperature potential. A constant fan may cool the stove too much where a limit/control will allow for a greater build of heat before it's put into the ductwork. Hopefully what you have will work, but that will require some good cold weather to find out.

 

[AIM]

I just wanna go on record and say that I have absolutely no input on this.:biggrin:

Interesting read though.

 

[Wood Doctor]

Not Good News

===

I have often thought of doing someting like that. Wonder what the county bldg dept and insurance company position on such a project would be????

The insurance company would kick your butt. A new insurance company would likely not insure you and if the existing company found out about the retrofit, they would bump the premium or kick you out. Insurance companies despise any homeowner trying to heat the whole house with wood.

 

[Whitespider]

On a woodfurnace, the limit is only wired to the damper or forced draft. If that temp is hit, the damper closes but the distribution fan will still run to cool the unit.

I didn’t find anything like that, at least not locally. They all had just two terminals that closed between the low and high limits… and opened on either side of the limits The one I’m using is for a fireplace insert blower.

The only thing that may pose a problem with the sensor at the flue is with a constant fan on, the stove may never hit it's temperature potential. … Hopefully what you have will work, but that will require some good cold weather to find out.

Actually I have it fired up again tonight; the blower came on early, before the plenum temperature had risen. But that didn’t stop the plenum temperature from eventually rising to the point we have nice warm air exiting from the heat ducts… just like Monday night it took about an hour for everything to come up to temperature from a cold firebox.

The blower starting early doesn’t bother me as long as everything comes up to temp, and it appears it does (the firebox draft is on low setting)… I just don’t want the blower cycling on and off as the fire dies. Remember, I’m using the gas furnace blower, and having it cycle on and off often is not really what it’s designed and engineered for. What remains to be seen is when the blower shuts down… I don’t want it to shut down too early.

 

[Whitespider]

The insurance company would kick your butt. A new insurance company would likely not insure you and if the existing company found out about the retrofit, they would bump the premium or kick you out. Insurance companies despise any homeowner trying to heat the whole house with wood.

I couldn't disagree with you more.
Not all insurance companies/adjusters/inspectors are crooks or idiots. I did not alter the original stove's construction in any way, nor did I alter any component... I simply removed those pretty porcelain coated steel trim panels and replaced them with panels of bare steel. Rather than install the stove in a living area surrounded by nothing but combustibles, I installed it in the basement surrounded by steel, concrete and brick. For that matter, most of my life I've had some sort of home-made wood burner... often built from scratch!

I often see these horror stories about insurance companies on this board... All I can figure is it's the difference between living somewhere like Omaha, and living somewhere far removed from any metropolis. If the insurance companies started treating us toothless, inbred hillbillies and hicks that way we'd kick their butts all the way to the county line. Heck, I've never even been asked by an insurance man if they could see my wood burner... About every five years or so they come out and take pictures of the place, step in the door and look around a little, point at the wood piles and ask, "Do you have a wood burner in the house?" I answer with, "Yep, in the basement." They nod their head and that's the end of it. Good Lord, I'd bet near 80% of the homes out here have some sort of wood burner... fireplace, stove, cook-stove, furnace, whatever.

 

[Whitespider]

UPDATE

It worked fine. I was up at 2:00 AM for my nightly pee and the blower was still running. The air coming from the ducts wasn't much over room air temperature so I went down and checked it out... the fire had burned to a bed of coals, the flue was still too hot to touch and the plenum was still pretty warm to the touch. Out'a bed at 5:00 AM, the blower has stopped... the flue is warm but not hot, and the plenum is just slightly warm to the touch.

I'm callin' it good... It does exactly what I need it to do, start the blower when the fire is burning and stop the blower when the fire is out... while still allowing me to have the gas furnace thermostat set at something lower for auto-backup, or even turn it up if wanted. The top of the sensor box is just a piece of steel folded over, so I can bend it up a little to let some heat escape, which will adjust the "timing" of the start/stop if needed. But I'll worry about that next fall when I have enough cool days back-to-back for experimentation... 'cause really, it would be fine the way it is.

This project is officially completed...

I have a new furnace for a total cash outlay of just a touch under $250.oo, which is a little higher than my original guesstimate of well under $200.oo... but I decided to re-work/replace all the flue pipe and ducting while I was at it, which did increase the cost considerably.

 

[Wood Doctor]

I couldn't disagree with you more.
Not all insurance companies/adjusters/inspectors are crooks or idiots. I did not alter the original stove's construction in any way, nor did I alter any component... I simply removed those pretty porcelain coated steel trim panels and replaced them with panels of bare steel. Rather than install the stove in a living area surrounded by nothing but combustibles, I installed it in the basement surrounded by steel, concrete and brick. For that matter, most of my life I've had some sort of home-made wood burner... often built from scratch!

I often see these horror stories about insurance companies on this board... All I can figure is it's the difference between living somewhere like Omaha, and living somewhere far removed from any metropolis. If the insurance companies started treating us toothless, inbred hillbillies and hicks that way we'd kick their butts all the way to the county line. Heck, I've never even been asked by an insurance man if they could see my wood burner... About every five years or so they come out and take pictures of the place, step in the door and look around a little, point at the wood piles and ask, "Do you have a wood burner in the house?" I answer with, "Yep, in the basement." They nod their head and that's the end of it. Good Lord, I'd bet near 80% of the homes out here have some sort of wood burner... fireplace, stove, cook-stove, furnace, whatever.

Disagree all you want. I'm only speaking from experience with two Allstate reps, one American Family rep, and two State Farm reps, all from different agencies. I imagine there are a few companies that will insure you or not bump the premium if already insured, but these outfits have a coalition in this neck of the woods. Perhaps being in a big city is a factor.