Hi The heat will not work when I go to heat but the induce draft motor stays running.When I call for a/c the outside condenser comes on and the induce draft motor continues to run and the blower motor won't come on.I check the motor,and thermostat and all wires to circuit board was okay.I replaced transformer and still have same problem and on the circuit board the yellow light will not cut off and the red light is very light and will not stop blinking is the circuit board bad.

Possibly, but first check your vacuum motors hoses. The motor is meant to pull a vacumm while checking that the out door draft is not plugged by a birds nest or other obstruction. If it is then the motor cannot create enough vacuum to trigger the vacuum switch. If the vacuum switch cannot trigger, then the motor runs continuously trying to create it, but the furnace gas valve or blower motor will refuse to run. It's a safety function to prevent carbon monoxide into the house. If the hose leaks or is cracked, the vacuum cannot be created either, or the Vacuum switch itself is bad (you can temporarily jump it out to test it.

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Originally Posted by memphis34

hi The heat will not work when i go to heat but the induce draft motor stays running.When i call for a/c the outside condenser comes on and the induce draft motor continues to run and the blower motor wont come on.I check the motor,and thermostat and all wires to circuit board was okay.I replaced transformer and still have same problem and on the circuit board the yellow light will not cut off and the red light is very light and will not stop blinking is the circuit board bad.

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Hi with the thermostat turned to heat and set high enough to call for heat . What happens. Is there 24 volts when you when you use a elect tester on the W and C terminals.