Should a hole develop in the tip of a thermocouple after it is installed in a gas heater and lighted?
The Thermoucouple should withstand the heat of the pilot without damage. If it is still working you are ok but I would get a backup in case it fails. Thermocouples work with 2 dissimilar metals fused together and they create a small voltage when heated. If the junction of the 2 metals is damaged then the Thermocouple will not work. Some manufacturers call there Thermocouples Thermopiles I have used universal replacements and never had a problem as long as they screw in correctly.