AC Blower Fan Stops and Doesn’t Restart

[brotherpeter]

So this is odd. With my be system set to cool and the fan set to auto I’ll notice that it feels too warm in the house and I go to the thermostat to check it. It is set to 73, the system reads cool on, the temperature is 79, the fan is set to auto but the blower is not blowing and won’t start.

The only way to get it to blow is to set the fan to on. This causes the blower to blow cold air for a bit but eventually the fan stops. I now set the fan to auto and it starts blowing again but it will stop again prematurely and not restart. I set the fan to on and the cycle restarts.

I have a new filter, a recently replaced new blower capacitor and all heat exchangers inside and out are clean.

Ideas?

Thanks for your help,

Peter

 

[MovingAlong]

So this is odd. With my be system set to cool and the fan set to auto I’ll notice that it feels too warm in the house and I go to the thermostat to check it. It is set to 73, the system reads cool on, the temperature is 79, the fan is set to auto but the blower is not blowing and won’t start.

The only way to get it to blow is to set the fan to on. This causes the blower to blow cold air for a bit but eventually the fan stops. I now set the fan to auto and it starts blowing again but it will stop again prematurely and not restart. I set the fan to on and the cycle restarts.

I have a new filter, a recently replaced new blower capacitor and all heat exchangers inside and out are clean.

Ideas?

Thanks for your help,

Peter

What system do you have and what does your owners manual list in the troubleshooting section?

 

[fitter30]

Brand and model of furnace? Take a pic of the wiring diagram. Call for cooling Y and G both get power sending it to outside unit and G terminal for the fan. No different than turning fan to on. Your not getting a G signal in cooling mode fan auto. Have you killed power to the furnace for a minute? Could be in the weeds. Put new batties init before killing cycling power.

 

[Innovate1]

Motor might be stopping on over temperature but more likely something in the furnace control board. Is the run time similar for first and subsequent runs? If it is over temp the first should be longer starting from a cold start. Really need more information on the system. Since you mention blower capacitor it must be an induction motor rather than a variable speed with electronic motor control so that makes it easier to trouble shoot. Put a meter on the power to motor and see if it goes to zero when the motor stops.