Here is how to PM these crazy things... FYI (from OEM service manual)

Arizant Bear Paws Service Procedures

PM Process:

1. Perform electrical safety procedure.
2. Install temperature test apparatus on end of hose.
3. Expose test pots by lowering filter shroud.
4. Replace filter.
5. Extend hose to full length.
6. Turn unit on to full value of thermostat control.
7. Allow 10 minutes to stabilize
8. Take reading (43.0C +/- 0.5)(if out, see calibration below).
9. Push over-temp switch to advance temperature uncontrolled.
10. Alarm lamp should light below 56C (There is no control of this value).

Calibration Process:

1. Perform PM procedure until step 6 completed.
2. Using small flat screwdriver, adjust temp reading gradualy through adjust hole under shroud.
3. When 43.0C is met and stabilized, proceed with over-temp steps 7 & 8 above.