I have a Rheem Classic Super High Efficiency Heat Pump which is about 5 yrs old. When I turn the thermostat to cool, the inside fan blows, the outside unit "clicks" once, but the outside unit fan does not blow and there is no cold air coming through the vents inside. There is a quiet "humming" sound that seems to be coming from the Direct Purpose (DP) Contactor (2 pole, 30 Amp, 24V coil). The connector on the top of the DP Contactor does go down connecting both poles when I turn the air conditioner on. The DP Contactor has been replaced twice in the past 5 years. Is it the DP Contactor again? Someone told me yesterday since the connector is going down on that the DP Contactor is working. He then told me that it's probably the compressor and try kicking it to get the piston running. Is it the compressor or something else? What other steps can I take before I call a professional? Thank you!

Call the professional. Unless you can read a schematic and have a good DVM you are going to be in over your head. It could be so many things that I won't list them. Kicking things will only risk more and bigger problems. If the compressor starts by kicking it, it needs replaced anyway. Just because the contactor pulls in doesn't mean it is good. The contacts could be bad. If that is the case, get the repairman to replace it with a 40 amp unit. They are about the same size. However if this is the third contactor, there is a good chance something else is wrong. High starting current or weak low voltage are two things that come to mind. Checking the LRA would be a good start. If you don't know what LRA is or how to measure it then call the repairman. Of course I have seen repairman that didn't know how to or have the tools to measure that! Really elevates my trust of the company!