Pitot Heat

[jhickam]

We are currently in the process of an annual on our 1973 337G and we found that the pitot heat was not operating. My question is what controls the heating element on the pitot tube assembly other than the panel mounted swith . Is it a themostat, timer or resistor or what. It stays on now after we reattatched the broken wire to the unit. It appears too hot to be safe to the point of smoking. Any ideas would be of great help.

Jim
N1871M

[Bob Cook]

Jim

I am not aware the stall heater has any thermostat. It runs in parrellel with the pitot heat. Due to temp it is not recommended to run while on the ground. They do get hot!

fyi

Bob

[GMAs]

the temp is controlled by a little sensor that is glued to the top of the Pitot tube... its a little black button looking thing... it controlles the temp of the heater element... if you look in the service manual you will see it under the pitot heat... it allows the temp strip to get just so hot... hot... and then it will trip the sensor... to control it... see parts manual...

the illistrated parts manual show it complete and with the wire tie in the right place to keep the thing from melting down... the heater strip is glued to the strut... and the pitot is glued to the heater strip with RED high temp RTV.... again you should not be leaving it on on the ground.. as it will make the paint change color... smile...

G.M>....