30 year old Bryant

bob_17

I have a Bryant gas furnace that is 30 years old . When the thermostat calls the blower will come on but the gas won't. I think the limit switch is bad. I have no wiring diagram. How can I test it..

VictoriaEnergy

testing controls

I'd be useful to know which Bryant, or take a pic showing the inside of the furnace.



Generally a lot of furnaces of that era have a control that will turn the fan on a set amount of time after a call for heat, so if you turn the thermostat up and the fan goes on after a delay, you are looking for an open flame roll out switch, the pressure switch not making, or the vent safety switch open.  Will the ignitor glow?  If the fan comes on immediately, then the fan high limit switch may be open.  Also note many furnace controls will run the fan for 2 min if the thermostat is calling for heat on power up.

 

Tim McElwain

Model number serial number

and some pictures of the controls, gasd valve etc. will help us to help you.