We have a 7 year old Tran XL1100 heat pump. Last year I took the top to clean the inside with the water hose. I was careful I thought not to get anything important wet. And ever since then the heat pump has made a low humming noise constantly can anyone tell me if I have a problem to worry about. It has cooled ok and this winter we are warm but the constant hum has me concerned. Tony
Condenser sections have a bad habit of having vibrations. Check and see if there is isolation pads under the condenser section. Should be under all the corners and one under the compressor.
Lastly put a brick on the top not blocking the fan and the noise may go away. move around until the noise abates. If that works then you need to check all the screws and bolts for tight. It is an nerve racking process some times.
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