I have a strong pilot light but the main burner isn't coming on... could it be the thermocouple?

I am an electrician only answering with what I little bit I have encountered to help you get heat sooner, until someone with more experience with gas burners sees this question.

Can be the thermocouple is defective, of not in proper contact with the pilot. There may be a certain setting for this contact with the flame.

The capillary tube from the TC to the gas valve may be kinked.

The gas valve may be defective.

If this is supplied by a utility company , many have good service techs that I think are reasonable. There response is usually very good. No gas utility wants to deal with a home explosion, that are getting more frequent due to the wide use of NG, Do -It - Yourselfers and the older infrastructure.

If the pilot valve stays open the thermocouple is good. Check for 24 volts from thermostat W teminal to ground, check for 24 volts along that wire all the way to the gas valve. Hope you find where its open at.

Man, did I get that a**backwards.

Thanks North.