Answer

Hello,

 

Any time a gas unit tries to start it goes through a certain process and it is as follows:

 

Tstat calls for heating

Inducer Motor starts

Gas Valve opens

Ignitor initiates

Gas Lights

Flame senser detects flame to keep the gas valve open

During the cycle there are a few safeties that are in operation.

 

These are the Fan limit switch, which controls when the flame comes on and off. There is a high limit switch, which keeps the furnace from getting too hot. There is also a flame rollout switch to keep the flame from rolling out of the unit and burning the house down.

 

The next time your system needs to be reset, i would check to see if the limit or the rollout switch are open. If the system tries to start and then locks out i would check the pressure switch.Also clean the flame sensor.

 

If all these things are fine, your control board may be malfunctioning.