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LeeH · Apr 30, 2007, 12:44 PM

I have a heat pump and in the winter I have no problems but when the A/C is used it is not the same. Sometimes when I turn on the A/C the fan on the heat pump doesn't come on. The first time it happened I went to check out the problem and when I set down a couple tools on the top of the unit outside, the fan kicked on. The house cooled off just fine. I know find that if the outside fan doesn't come on, I just have to go out and lightly hit the top of the unit and the fan kicks right on. What could be the problem? I would like to get it fixed so that the unit doesn't run too long without the fan coming on outside.

Thanks in advance for the help.

Lee

JackT · Apr 30, 2007, 01:28 PM

You could have a contactor that's going bad or a loose connection. Some units also have a time delay relay that won't allow it to come on right away. There's many different types and styles of delays, some will delay it only after it turns off, some will delay it when it first calls for cooling, and most digital thermostats also have built in delays. These all are designed to prevent short cycling of the unit.

LeeH · Apr 30, 2007, 01:32 PM

Originally Posted by JackT

You could have a contactor thats going bad or a loose connection. Some units also have a time delay relay that won't allow it to come on right away. There's many different types and styles of delays, some will delay it only after it turns off, some will delay it when it first calls for cooling, and most digital thermostats also have built in delays. These all are designed to prevent short cycling of the unit.

Is the contactor something that can easily be replaced? How can I know for sure that it is the contractor that is not functioning correctly.

I don't think it is a delay problem because yesterday the A/C was running for over an hour before I realized that the outside fan was not running.

Lee

JackT · Apr 30, 2007, 01:56 PM

The contactor has two big wires on top and two big wires coming off the bottom with two small control wires connecting some wheres else on it. The contactor may have some bad contacts that don't make good contact anymore or the coil could be going bad. You also could have just a loose connection or a bad connection on the circuit board. If you're a mechanically inclined person, shut the power off and remove the cover from the unit. Turn the power back on and set the thermostat to cool, take something that's a nonconductor of electricity and lightly tap the contactor and circuit board and see which one brings on the unit. Please don't try this unless you feel safe doing it. There will be live exposed conductors.