How accurate is your PF100 thermostat?

Not open for further replies.


Jan 23, 2011
Dunbarton, NH
Like the title says, how accurate is yours? Mine seems to be way off, I set it to 70 and while it is 74 in the house and it fires the stove up... brings the house up to 75-76. So I put it down to 65 or so and now its out and not calling for heat. I've tried 68ish and it still fires up. The house is currently 75 and I know if I put the dial at 68-70, it will fire up again. Seems to be over 5 degrees wrong.

Is their some calibration procedure?


Minister of Fire
Nov 1, 2009
Brimfield, MA
I was told by Harman that in the case of a pellet furnace at least, if the wall controller does not agree with a digital thermometer you have near the wall controller, do not slip the dial on the wall controller to get them to agree. You can use the "temp knob" that you would use in manual to trim the wall controller running in automatic.
The temp knob has a "normal" setting that you run at in automatic. If that "normal" setting is off from the digital reading, you will see that the temp dial is labeled 1-2-3 normal 4-5-6. The 3 numbers below normal are -1 degree increments and the 3 number above are +1 degree increments from the wall controllers dial setting. So you can trim the temp setting by +/- 3 degrees.

You can also try mounting the thermostat (wall controller) off the surface of the wall with some pieces of Styrofoam or some other insulating material as a stand off. Sometimes the thermistor inside the controller will pick up the temp of the wall instead of the surrounding air.

Have you ever loosened the dial and slipped it to agree with a digital thermometer in the room? The dial might be off from where it should be. See if the marker on the dial sits on the line before the 60 (55) when fully counter clockwise. If not, turn the knob completely counter clockwise, loosen the set screw and set the dial marker to that line and tighten the screw. Then see what you get. Also make sure the location is good being on an inside wall, centrally located where there is no drafts but good air circulation to the wall controller.
Last edited:
  • Like
Reactions: DoWnAqT
Not open for further replies.