Should thermal sensor on fan touch b

  • Active since 1995, is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.


Jan 14, 2018
Denver, CO
If anyone has the Green Mountain 60 I would love to ask if your thermal sensor on your fan touches the back of your stove. More info:

I've had my Green Mountain 60 + fan kit for a year and it's been great. One thing I've noticed early on is it takes forever for the fan unit to turn on. I understood this is because the stove itself needs to warm up so that the thermal sensor (called a snap disc for some reason) turns on the fan. Except this takes an exceptionally long time, far longer than you would think because the back of the stove is already hot and I'll have exit gas temps approaching too hot (a perfect time to pull heat away and redirect it into the room with this fan).

I cleaned my chimney for this first time and had to take the fan kit off the back. Once I removed the heat shield I could clearly see the snap disk is sitting a 1/2" away from the back of the unit. The back of the GM60 is very slightly curved where the fan sits. The fan assembly is perfectly straight however. So the sides sit away from the back of the stove. I don't know if this is intentional so the sensor doesn't quickly burn out. Once the stove reaches temp the fan will stay on until the fire is completely out and then the fan will begin cycling on and off until the stove is cold.

The snap disc is enclosed in a small metal box and attached by screws. I removed the box and found that I could move the snap disc to the exterior of this box and use the screws to adjust the distance from the box I would like. This way I can have the snap disc touching the stove. Except now I'm wondering if this is bad.

Does anyone have a GM60 with fan and can tell me if it looks similar to them?
Not familiar with this unit, but every snap disc I’ve seen needs to be in direct contact with the stove body.
Thanks, I guess that would mean it's okay to be touching it.
Some come with magnetic thermal switches.
Some come with magnetic thermal switches.
Interesting, so I'd assume at least they are intended to be touching the stove. I just checked, however, and mine is not magnetic. Thanks
Snap discs are crude mechanical thermostats and have lots of hysteresis -- meaning there is a huge gap between their turn-on and turn-off temperatures. This results in them taking a long time to snap when heated and a long time to shut off when cooled. Unless you have a need for the blower to operate automatically and unattended, a jumper wire bypassing the snap disc would allow you to use the power switch to turn the blower off and on when you choose. Some blowers already allow you to use the switch to override the snap disc.