Stove Burning Too Hot...

[Chuck the Canuck]

Hi. I'm using my little 1.9 cf stove, located in the basement, and burning 24/7 in order to heat the 1 story house (we have an air to air heat pump to pick up the slack if the stove goes out). Thanks to you all, I've established a good convection loop between the basement and the main floor with a fan, and in general we've kicked the heat pumps butt, reducing our power bill in the process. The problem is that the stove always seems to run hot, really hot, after the secondaries kick in, usually running anywhere between 700-750 F on the stove top (measured with an IR gun) and 350-390 F on the single wall stove pipe (measured with a magnetic thermometer). I absolutely always have to monitor the burn very closely when I load it (3 times a day, once in morning, once with a small load between 5-6:00pm, and the overnight load around 10ish), because the stove top can easily take off and hit 800-850 at times (the flue will get up to around 400-410 F at these times). I've tried shutting the air down early, this seems to help a bit, but in reality it just seems to delay the eventual take-off; if I'm lucky it the stove top will only get as high as 700-725 F and then I breathe a sigh of relief, but most of the times it hovers around 750-765 F and I never really know if it's going to take off or not, so I have to just sit and watch and wait. And that's when I realized that this is probably burning through my loads of wood faster than it should. I can't help but wonder if I have too much draft pulling on the stove which feeds the secondaries so that they always take off like crazy regardless of how fast or how much I turn the air down. The chimney info is thus: approx 6 feet of single wall stove pipe up to the basement ceiling, another approximately 16 feet of proper class A chimney running through the house, and it looks like about 3 feet of chimney outside the roof, for a total of around 25 feet all together from the stove top. No obstructions or neighbours anywhere near me or my house. Could this be the problem and if so, how would I address it? I've looked all over the stove and there doesn't appear to be anywhere that I can use the old magnet trick to reduce the secondary air intake. I'll add a picture of the air flow for this particular stove from the owners manual in case it helps anyone with any ideas.....

Cheers,

 

[Chuck the Canuck]

I guess I forgot to add that I'm also quite worried that running the stove this hot is going to kill it way before its' time.....

 

[begreen]

You could add a key damper to the stove pipe to reduce draft.

 

[Chuck the Canuck]

You could add a key damper to the stove pipe to reduce draft.

Yeah, I think I'll pick one up and put it in tomorrow morning. I had to turn the fan on again 30 minutes ago when the stove top hit 780 F.......

 

[Chuck the Canuck]

So would I get the 6" cast iron damper, like this one?

(broken link removed to http://www.kent.ca/kbs/en/product.jsp?navAction=jump&navId=1771&prdId=664243&skuId=664243&catalogId=1771)

 

[begreen]

Yes, you've got it.

 

[_CY_]

The problem is that the stove always seems to run hot, really hot, after the secondaries kick in, usually running anywhere between 700-750 F on the stove top (measured with an IR gun) and 350-390 F on the single wall stove pipe (measured with a magnetic thermometer). I absolutely always have to monitor the burn very closely when I load it (3 times a day, once in morning, once with a small load between 5-6:00pm, and the overnight load around 10ish), because the stove top can easily take off and hit 800-850 at times (the flue will get up to around 400-410 F at these times). I've tried shutting the air down early, this seems to help a bit, but in reality it just seems to delay the eventual take-off; if I'm lucky it the stove top will only get as high as 700-725 F and then I breathe a sigh of relief, but most of the times it hovers around 750-765 F and I never really know if it's going to take off or not, so I have to just sit and watch and wait.

IR thermometers are not terribly accurate depending on what temps/materials your particular gun registers.

a digital pyrometer is the most reliable method to double check for high temps. for lower temps you should calibrate to ice water.
properly settled a large glass full of ice cubes just barely covered with water will always be 32f .. any thermometer can be calibrated this way.

 

[STIHLY DAN]

I had the same problem but worse. Try the key damper, this should work. If it doesn't, put a baro in.

 

[BrotherBart]

Don't even think about putting a baro damper in a wood stove pipe.

Start closing down the air sooner and get over waiting for "secondaries". Run the stove based on the stove top temp. Not bullshit that you read here about secondary burn. Run the stove at temps to heat your house. And not to melt the stove. Not some fantasy about secondary burn.

 

[Chuck the Canuck]

Don't even think about putting a baro damper in a wood stove pipe.

Start closing down the air sooner and get over waiting for "secondaries". Run the stove based on the stove top temp. Not bullshit that you read here about secondary burn. Run the stove at temps to heat your house. And not to melt the stove. Not some fantasy about secondary burn.

I'm a bit confused by what you're trying to say here BB? Do you disagree with the idea of putting in a key damper to control an over active draft?

 

[HotCoals]

He saying not to use a barometric damper in the flue and I concur. Try the key damper though.

 

[Chuck the Canuck]

He saying not to use a barometric damper in the flue and I concur. Try the key damper though.

Got ya! I just picked it up. I'll keep ya'll posted.

 

[Chuck the Canuck]

Key damper is in! Soon as I finished installing it I filled up the stove and lit a fire. Sure enough the stove top temp started climbing towards red line territory (685 F and still climbing) as the secondaries continued to build, billow and roar (the air was already completely shut down on the stove). I gave the key a little turn from the 12:00 oclock position to about the 2:00 oclock position and presto! Within 10 minutes the stove top was down to 650 F. I just check again and it's at 620 F. Looks like a winner...

Thanks all.

 

[HotCoals]

Good to hear!

 

[Chuck the Canuck]

Good to hear!

Thanks HC. I feel a bit better about the draft now, but one thing I'm curious about; what if I were to switch out my stove with a new one (either a Drolet Austral or an Englander NC 30) this summer. Would I expect to still need to use the key damper from now on?

 

[Ram 1500 with an axe...]

Thanks HC. I feel a bit better about the draft now, but one thing I'm curious about; what if I were to switch out my stove with a new one (either a Drolet Austral or an Englander NC 30) this summer. Would I expect to still need to use the key damper from now on?

Glad it's working out, keep us updated as to whether this was the right choice....... New stove may mean new situation, got to go with the flow......

 

[HotCoals]

Thanks HC. I feel a bit better about the draft now, but one thing I'm curious about; what if I were to switch out my stove with a new one (either a Drolet Austral or an Englander NC 30) this summer. Would I expect to still need to use the key damper from now on?

Who knows...but maybe and if not it wont hurt for it just to be there.
Cheers!

 

[BrotherBart]

Thanks HC. I feel a bit better about the draft now, but one thing I'm curious about; what if I were to switch out my stove with a new one (either a Drolet Austral or an Englander NC 30) this summer. Would I expect to still need to use the key damper from now on?

For sure. If that lil pup is going thermonuclear you ain't gonna believe what happens with a 30-NC full of dry wood.

 

[Chuck the Canuck]

For sure. If that lil pup is going thermonuclear you ain't gonna believe what happens with a 30-NC full of dry wood.

I can't wait!

 

[jophysx]

Thanks for posting your results with the key damper. I have about a 25+' chimney too, and my insert is right on the edge of being difficult to control. This year the door seal was not quite as tight as it should be and the stove became a real pain to control. Had to watch it very close as you described. I fixed the door problem and now the stove is ok. But still, if the conditions are right it can get away from me (large reload when the stove is a little too hot, dry wood, small splits, really cold weather, . . .). I think it would be helpful to have direct control over the draft strength with a key damper.

I'm also considering an insert for the basement floor. That one would have a 35-40 foot chimney! Definitely need some kind of damper for that. Maybe a 5" or 5.5" pipe too.

 

[_CY_]

so did you ever check you thermometer for accuracy? not unusual to be 100f+ degree off

 

[Seasoned Oak]

I guess I forgot to add that I'm also quite worried that running the stove this hot is going to kill it way before its' time.....

Did you get the blower that fits this stove. Iv found the blower can go a long way to cool down a hot stove and also warm up a cold house at the same time. I consider 600-700 the sweet spot on my englander 30. I try to keep it from going much over 700 or much below 600 when i want maximum heat. Theses stoves seem to burn much cleaner with a stovetop over 550. Iv found i can control the temps on all my stoves with the air control and the blower fan. Some taller and insulated flues may need more control.

 

[Chuck the Canuck]

so did you ever check you thermometer for accuracy? not unusual to be 100f+ degree off

Cy, I just put some ice cubes in the freezer to check the accuracy of the IR gun. It from VWR, a laboratory supply company and it claims to be traceable on the label. Likewise, it tracks very closely with the magnetic flue thermometer. I guess the water glass full of ice can be considered my low temperature calibration standard.

 

[Chuck the Canuck]

Did you get the blower that fits this stove. I

Oakster, no I didn't get the blower when I purchased the stove. I thought about ordering one a week or so back when I started to get frustrated with the potential overfiring, but then I found out they want $280 plus tax for one. The pedestal fan I have in the basement does a pretty good job of cooling down the stove top when it starts getting too hot. I guess I was really starting to question why the stove wanted to over fire all the time, and it seemed to me that an over active draft was the most likely culprit. I'm in complete agreement with you about running the stove top between 600-700 F, and even pretty comfortable with it running up to 725-750 F but, Holy Hannah, it just kept wanting to go higher and higher and higher..... I'm hoping the key damper is going to help keep it from taking off like that. I have to admit I'll be happy to replace this stove in the off season with a new one. It's just a wee titch too small for what I've been asking it to do, although it's done an admirable job. My electric bill this past three months (for November, January and February) has dropped down to the same as it is for the summer months, so I've been saving a bundle there. The goal for the new stove will be to upgrade in terms of quality and user friendliness. I'll probably leave the key damper in for at least the next heating season just in case it's required.

Pics of the key damper:

 

[_CY_]

Cy, I just put some ice cubes in the freezer to check the accuracy of the IR gun. It from VWR, a laboratory supply company and it claims to be traceable on the label. Likewise, it tracks very closely with the magnetic flue thermometer. I guess the water glass full of ice can be considered my low temperature calibration standard.

View attachment 128775 View attachment 128776 View attachment 128778

sorry it doesn't work that way .. IR guns can be off depending on reflective area measured.

second pic below is a calibration check pic for several different thermometers .. all were right on for ice cube barely covered with water test of 32f

an ice cube can be colder than 32f .. but ice floating in water settled will always be 32f .. which is the standard way to calibrate a thermometer.

two digital pyrometers, one with thin probe rated to 2,000f .. Check-it is calibrated to NIST traceable standards.
(broken image removed)

calibration check at room temp .. note weston is off 3f degree .. all were dead on at 32f during ice cube/water temp check. Atkins digital is calibrated to NIST traceable standards.
(broken image removed)