"Rick" wrote in message
.net...

"dave" wrote in message
oups.com...
Thank you for all the advice. It is an old Honeywell manual
thermostat.
Indeed there is power to the furnace, with a switch box. The
furnace
was installed 1992. I have watched the burner sequence many times.
The
thermostat is indeed calling for heat as it should. The ignition
is
firing red hot, but it doesn't appear to be getting gas for those
several hours. This is what made me think it was a gas pressure
problem
upstairs at peak hours (when people are at home in the evening),
but
that may be ignorance on my part. I have looked all over for the
timing
mechanism that could explain the problem but can't find it. There
is
no
wiring that would explain it.
I'm beginning to like the ghost explanation. Anyway, my wife is
pulling
her hair out. And you can imagine what no heat at bedtime is doing
for
the more personal aspects of my life. Argh.


There should be a wiring diagram on the inside of unit, most likely
on
one of the panels...


Not that it will help you, though. If the igniter is coming on it
sounds like any pre ignition interlocks are OK. Can you hear the gas
valve solenoid clicking? It should attempt to light a few times (with
a delay between attempts) before it shuts off and resets the sequence.

Could be flaky ignition module or gas valve, would need to check
voltage to solenoid when it's trying to light.....