I have a Trane compressor outside. The unit comes on and the interior blower comes on for a few hours and then stops blowing. I tried to turn on the fan via the thrmostat and it does not work when it shuts down but otherwise works fine so its not a wiring problem. The outside unit continues to work.

I replaced the interior blower motor as I thought the thermal protection was defective. The problem remains.

If I shut off the exterior unit and interior unit via the main circuit breaker and leave it off for a few hours everything works fine.

The fan blower works fine in heating mode.

Is there a fan blower control in the condensor that controls the interior blower? There are two wires coming from the condensor to the control box on the furnace.

Thanks,

Richard

letmetellu

Are you positive that the inside blower quits running? or do you just quit getting air through the vents?

If you have a problem such as a dirty filter or low on freon or some of the vents closed, the coil above the blower can freeze over and when it does it will stop the air from coming out of the vents. To me this sounds like it could be your problem.

The only other reason that I can think of that the motor would run for hours and then stop is a loose wire or a bad thermal protector.

richord

YEs, the fan is definitly not running but the compressor continues running. The only thermal protector I know of is on the motor and I repalced the enire motor and capacitor.

letmetellu

You did not say how old your unit is and if it is very new it has a circuit board and it is probably a relay on the board. If you do not have a CB then is is a fan relay in the control box and if you are lucky it will be the plug in type, a new board is very expensive.

richord

The unit was installed in 1991 and has a control box on the furnace model VR8204-S8600H.

Do you know if there is a relay for the fan blower that is only for the AC not the furnace, since the blower works fine in the furnace mode?

Is the CB you are referring to in the compressor on the furnace?

acetc

He is refering to the board in the furnace, the fan will work off a different relay for heat if your furnace has a printed circuit board. this is to bring the blower on in low speed during heating , if you don't have this board then you will have a relay to bring on the fan in cooling and a separate fan switch to bring it on in heating. Check for the easiest solution, a loose wire, unplug and check all connections.