Thermometer popped off stove pipe

[stefan]

Greetings,

Last night was not monitoring my jotul 3 for a few minutes -- suddenly noticed the stove pipe thermometer had maxed out at 900 degrees.
The magnetic thermometer actually popped off the pipe onto the floor. I immediately shut down air supply -- flue was already shut down -- but the stove kept on blasting for a few minutes, before it died down. Two questions: Could this have caused any damage to stove parts? Is there a stove pipe thermometer available with an audible alarm that can be set? Any other advice on how to avoid sudden stove temp creep...

 

[bluefrier]

[quote author="stefan" date="1232258714"]
Could this have caused any damage to stove parts? Yes it could but it is unliklely, most stoves could handle a little abuse. was the stove glowing anywhere? Is there a stove pipe thermometer available with an audible alarm that can be set? not that I know of...one member rigged up an alarm though...try to search the site and see if you can find that post. Any other advice on how to avoid sudden stove temp creep... Yes, remember that you are playing with fire.[/quote]

 

[Valhalla]

Magnets will not hold at that high temp.

What kind of flue setup?

 

[stefan]

Neither the stove or pipe was glowing. Also checked pipe outside and did not see anything unusual.

The flue is located on pipe about a foot or so above the stove top.

Sounds like a probe type thermometer would be safer.

 

[Pagey]

My Rutland won't hold any ANY temp now, whether 200 or 600F.

 

[Corey]

Sounds like you found the Curie temperature of your magnet (the point at which the magnet is no longer magnetic):

https://www.hearth.com/talk/threads/4944/#52895

I doubt ~900F did any permanent damage. Repeated operation at that temp would probably cause the metal to oxidize or get 'scaly' and eventually, you'd have a hole in the pipe. There are some high temp alarms that can go that high, but they are usually specialty equipment and cost a decent amount...not something you're likely to pick up at the local home store.

I guess you could search for a magnet with a curie temp about the temp you want the warning, then the 'clunk' of it falling on the floor would be your alarm.

 

[raybonz]

At those temps I would have jumped off too!


Ray

 

[WES999]

The directions on stove thermometers typically recommend safety wiring or screwing the thermometer to the pipe to avoid falling off at high temps.

As for the high temp alarm I have one.

here is what I posted in another thread.

Well, this seems like fairly common occurrence. Over heating the flue can happen in just a few minutes with a load of very dry wood, such as pallets or mill ends which heat up especially fast.

What I have done is to make a flue temp alarm that will sound an alarm if the flue gas exceeds the set temperature. It can also monitor stove top temp by using a magnetic mount surface probe. Generally what I do is to load my stove up full, leave the air open until the flue temp alarm sounds ( I have mine set for 850*, internal temp) Then I turn the air down some. This way I have little fear of over heating the flue, even if I am burning something like Pallets or pine.

I have received several inquires asking if these units are for sale. I have decided to start making a few and offering them for sale, as it seem like a product for which there is a real need, and nothing really available as far as I can see.

Here is a video I made showing how it works. And a link to some other posts showing some pics.

http://www.youtube.com/watch?v=PXMpyJ6c150

https://www.hearth.com/talk/threads/32390/#342638 (see 4th post down)

PM me if you are interested or have any questions

 

[Valhalla]

Yes, safety wire is the best way. Some brand magnetic thermometers came with it years ago.

 

[oconnor]

Some of the thermometers will even take a screw thru the middle to hold them in place.

As for a temp alarm, I had a unit for use on single wall pipe - small 3x2x2 inch box. Took a 9volt battery, and squaked whenever the temp hit around 850*F. Bought it at a stove store for 6 bucks about 6 years ago. It is on the right side of the flue in this pic of my old stove (never knew what brand the stove was - stainless firebox and poor air control though.) If I find the unit again, I'll post a better pic.

 

[Valhalla]

Interesting on the 9V battery operated sensor. I'm surprised that the 9V battery could endure anything over 300F!