Thermocouple for Mr. Heater & Heat-Star Propane Heaters Part No. 26655 The 26655 Thermocouple is the Mr Heater 10 Inch thermocouple for the combustion chamber to the junction block on several of the Mr Heater and HeatStar portable construction heaters. This 26655 Thermocouple was used on the following Mr Heater and HeatStar models: Mr Heater: MH55FAV, MH85FAV, MH125FAV HeatStar: HS55FAV, HS85FAV, HS125FAV This part is compatible with the following machines: Heatstar HS125FAV Forced Air Propane Construction Heater HS55FAV Forced Air Propane Construction Heater HS85FAV Forced Air Propane Construction Heater Mr. Heater MH125FAV Forced Air Propane Construction Heater MH55FAV Forced Air Propane Construction Heater MH85FAV Forced Air Propane Construction Heater