[16x80]

vlink55

You could have a couple problems.

You have already ruled out the thermal couple, It is possible that you are getting less than 24v to the gas valve which would allow it to keep the pilot light lit but not enough to open the gas valve!

You could also have a bad main high limit (located on the heat exchanger area with two wires going to it) (one of them is the red one on top of the gas valve) This limit should be normally closed (reading continuity) with no wires hooked to it!

Question is the pilot light getting bigger when you make a call for heat or does it stay the same size regardless?

16x80