Well it turns out that the pressure sensor was shutting down the gas valve
due to restricted air flow caused by leaves in intake pipe. Removed leaves
and furnace operates normally. Thanks any way.


"Henry Gawluk" wrote in message
.. .
Our old Carrier Weathermaker Furnace (Model 58SX080-BC-1) seems to be
acting abnormally. When heat is called for the exhaust fan motor starts
up, the pilot kicks in approx 40 to 50 seconds later, if the pilot doesn't
shut off, then the burners ignite, and the blower motor turns on and blows
heat. the burner shuts off approx 40 to 50 seconds later with a pfffffft
sound and the blower runs for another 30 or 40 seconds until chamber
cools. It all starts over. Pilot lights, sometimes burner lights or pilot
goes out, If burner lights, blower blows, but burner shuts off with the
pfffffft sound.Meanwhile the temperature never gets to thermostat setting.
I will be calling service department tomorrow, in mean time any
suggestions or causes?
Thanks for your help.