Stovepipe Offgassing, Over-Firing, and Smoke Alarms

[PolrBear]

I have a First Alert SMI100-AC smoke alarm installed on the ceiling about 15' away from my Hampton H300 wood stove. It's an old stove, but the connector pipe (double wall telescoping Selkirk) is fairly new and has seldom seen a surface temperature over 400F due to the way we run our stove. Should the pipe temp get to about 500F or more, we begin to smell that hot paint/burnt crackers odor you get with new pipes - and shortly thereafter, the smoke alarm sounds. This is a big problem because it usually happens after I build a big overnight fire and then fail to turn the intake down far enough - and the interconnected alarms in the children's bedrooms then wake everyone up while I come flying out of the shower to hit the cancel button.

The SMI100AC is an ionization type smoke alarm, so my theory is that it basically "smells" the tiny offgassing particles from the new-ish stovepipe. Does this make sense? If so, should I just take a cold day, unhook that smoke alarm, and fire the living daylights out of the connector pipe at, say, 600F, until the smell is all burned off? What about changing to a photoelectric smoke alarm? Is 15' close enough that I'd likely get false alarms while reloading the stove?

Advice and experiences appreciated.

 

[stoveliker]

600 on the outside of double wall pipe is far, far too hot. I suspect that it is in the range where the pipe could be compromised already...
For single wall, the outside temp is half the inside temp. For double wall I don't know but I would not be surprised if it's a quarter...

You need to buy an auber with an alarm so you get warned to dial down the stove when the internal temperature reaches 1000 or so.

There's a fire in your home. To keep it contained you need to pay better attention.

 

[MongoMongoson]

I had to put a new battery in my IR gun this morning. I never use it anymore, but you had me curious. I use an in-pipe thermocouple, similar to what stoveliker recommends.

I have maintained a fire at over 650 degrees, as read by the thermocouple, for over 30 minutes. For your reference, this is my double-wall surface temperature at an internal pipe temperature of 671.5. Different stove pipes measured at different points will probably give you different readings.

I have the blower going, and on my stove that blows across the stove top and the base of the stove pipe at the stove collar. I imagine if I did not have the blower going I could get a higher reading where the stove pipe connects to the collar. This reading was taken maybe 9 or 10" above the stove top. The thermocouple is at 18".

The surface temperature of the double wall is not very useful for helping you run your stove, but I agree with stoveliker. 400+ is running it too hot unless you are checking temperature right at the stove collar.

 

[Crab]

In addition, FYI I have an Auber digital internal probe, right now it reads 625degF, my IR gun reads 200 on the outside of DVL double wall. The internal temp has been stable for 1/2 hour

 

[Eman85]

my DW pipe still gives off a smell if we get distracted and don't engage the cat and the pipe temps get high, pipe is a few years old and has reached the stink level multiple times. You can see the difference in color of the pipe, lower section is duller. My smoke detector is a lot closer than yours and rarely if ever goes off.

 

[PolrBear]

my DW pipe still gives off a smell if we get distracted and don't engage the cat and the pipe temps get high, pipe is a few years old and has reached the stink level multiple times. You can see the difference in color of the pipe, lower section is duller. My smoke detector is a lot closer than yours and rarely if ever goes off.

Do you happen to know the model number of your smoke detector, or whether it's an ionization or photoelectric one?

 

[begreen]

Surface temps on double-walled stove pipe are almost worthless. Get a probe thermometer to know what the flue is doing. I'm partial to digital because of the quick response, alarm setting, and ease of reading across the room, but an analog probe will also work. Condar makes a decent one.

 

[PolrBear]

On probe thermometers - why is it okay to make a hole through the double wall for the probe? Previously I was told that a hold in the double wall is a safety concern and would fail inspection.

 

[begreen]

Not a safety concern. Every joint of stovepipe is to be secured with 3 screws. Holes are needed for those screws. The probe thermometer hole is mostly sealed by the probe itself and then the magnet on the outer layer. What is a safety concern are large gaps in stovepipe connections because of the cool air that is admitted at those points which can lead to creosote buildup.