pilot light keeps going out

ddenny

hello

       I take care of some 35 year old gas fedders furnaces in an apartment complex. pilot light keeps going out in one apartment. I changed the thermocuple and pilot assembly. It works afine through a couple cycles but I'll get called back in a day or two. I've changed the heat exchanges on other units several times because of pilot lights blowing out but when the heat exchanger has a hole in it you can watch it blow the pilot light as soon as the thermostat is satisfied. this isn't the case with this apartment, the pilot flame doesn't seem to be affected by blowing air. so for that reason I think the heat exchanger is probably ok. could something be wrong with the gas valve not opening in response to a good thermocouple? If the thermocouple is good and it's sending a strong enough signal to the gas valve but it drops out after a day, should I suspect the gas valve is borderline defective? how can I check that other than by changing the valve and see what happens?                  thank you 

Tim McElwain

Just click resources

at the top of the page and then Hot Tech Topics and look for "Thermocouple Testing Procedure" that should help you.