Tempstar Air Handler FXM4X4800A1 Installed 09/2010.
Tempstar Heat Pump TXH548GKA100 Installed 09/2010
A/C system controlled by Carrier Comfort Zone 4 Zone System installed in 1992.

When AC comes on the Air Handler Blower runs for about 20 seconds then stops for 3 seconds then runs for about 20 seconds. This happens the entire time the system is running.

I turned the thermostats Heat Switch Off & the Cool Switch Off and turned the fan Switch from AUTO to ON & the blower motor did the same thing, blower runs for about 20 seconds then stops for 3 seconds then runs for about 20 seconds.

NO burning or other smells coming from the AC unit.

I opened the air handler service panel and this unit DOES NOT have a run capacitor.

The blower wheel (squirrel cage) spins freely and is quiet.

The evaporators metal housing has what appears to be rust on the side under each of the copper lines where it comes out of the evaporator and goes back in. Not sure if this is normal for a 24 month old unit?

The evaporator coils fins are clean.

The system is running fine & the house is cool. All three filters have been replaced.

Carrier Comfort Zone 4 Zone System installed in 1992.

It is probably the Carrier Zone system causing the problem. Bypass the zone system if you can and see what it does. It is probably some kind of a time delay in the control system somewhere that has lost its setting or a sensor for cooling control.

HVAC1000,

Thank you for responding.

It looks by your Avatar you've traveled to the east?

I just found a VERY Honest HVAC repair company that quickly diagnosed this problem today 04/29/13.

A component inside the X-13 blower assembly motor was bad. The technician told me Tempstar has had a lot of problems with the X-13 motor and he has replaced a lot of them.

AC is now up and running without shutting off every 20 seconds as it did before.