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My internal heat pump has recently begun to make a loud humming/vibrating noise after shutting off. Why?

System is pretty old. Noise hums for about a minute, stops, then restarts. Occurs about 10 or so times then stops. Only happens after heat shuts off. Cooper piping gets very very hot, ,perhaps unrelated. I know very little about this subject, so any help appreciated.


OK, more details...

Last night I tried turning off the heat because the noise was getting really irritating. The noise CONTINUES to happen when the thermostat is set to off. The humming/vibration starts softly, gets louder and louder, and then stops. It is replaced by the sound of either water or air, like an opened valve. Then after a couple seconds the noise starts again. Sometimes the noise cycles are much closer together, sometimes farther apart.

I have no technical know-how in this field, so even the most basic things I could do myself may be a challenge for me.


7 Answers

  • 1 decade ago
    Favorite Answer

    the only thing in the air handler (inside part) of a heat pump that could be making a humming sound when the fan is off is the trans former.

    the copper pipes are supposed to be hot in heat mode. you might want to look at this link. it explains how a heat pump works.

    i really believe that the buzz can be fixed be tightening the screws that hold the transformer. you can do this your self unless you dont feel comfortable with it. if you do try it, turn off the power first.

    hope this helps,

    Possum, hvac guy

  • 1 decade ago

    Could be the contacts to the compressor motor. The contacts give off a type of pheromone when they open and close that attracts male worker ants. The ants follow this smell and become lodged in between the contanct when the compressor turns on and off. Thus providing a block for the contacts to contact. I got this information from a service tech. If your heat pump is also your air conditioner which most likely it is. The copper tubing supplies the freon to the unit compressor. Freon works in a heating cycle to cool the air. Strange isn't it. But true!

  • 1 decade ago

    You really should see a doctor about that. Just kidding. Sounds like the compresor is about to take a crap. Have it serviced (lube, freon) which should be about $50. Might help. Odds are you will need a new compressor soon.

  • 1 decade ago

    May be several things fist thing is to make sure the filter is clean. if it is then check to see that there is lots of air being moved. If not then the indoor coil is plugged and should be cleaned. If those things were fine then it may be your contactor is sticking and call a repairman.

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  • 1 decade ago

    make sure you have good air flow, high pressure in pipes could be equalizing making noise or a check valve in system leaking. relays and transformers can hum.

  • 1 decade ago

    Sounds like a bearing, no kidding, and you'd better do something quick.

  • 1 decade ago

    need more details, but you would probably have to change your pump prutty soon, happy holidays

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