I have an older Trane XL1200 gas pack furnace/AC. I just tried to turn on the
furnace and nothing happened. Looking at the control board the led code told
me it was a pressure switch problem. The inducer fan was not turning (rusted
stuck). I replaced the inducer fan and now the furnace will go through the
start-up sequence (check high limit switch, check flame rollout switch, turn
on inducer fan, check pressure switch, turn on spark igniter, send voltage to
gas valve) but it fails to light and goes into system lockout (no flame). I
checked the voltage to the gas valve and it was 60V AC while the igniter was
firing! The gas valve would click but the furnace would not fire. It should be
24V AC. To check the gas valve I disconnected the wiring from the valve and I
connected 24V AC to it and it would click but I could not hear gas flowing or
smell any gas. Do you think the gas valve is bad or the control board since it
is supplying 60V AC to the valve?

--
for full context, visit https://www.homeownershub.com/mainte...m-1202400-.htm