[JBG420]

Apologies if I mix some of the terms up. Electric heat pump/AC.

With heat setting on, when the outside unit kicks on, there are 5-6 loud metal-on-metal bangs. House is maintaining temp and that banging is intermittent.

I took the condenser unit fan off the top and could see the compressor had loosened from the base. I tightened the 4 bolts holding the compressor and that seemed to help - for a bit. Now the banging is back.

Anything else I can easily check?

 

[spitz1234]

Fan bearings?

Sent from my SM-G960U using Tapatalk

 

[yuri]

Make a video of it and post it on You Tube and put it here.

Those bolts should never come loose so I suspect maybe your compressor is hitting the side of the walls/can and maybe has a problem.

It rides on 3 springs internally and maybe one is broken.

If we could hear it maybe someone will recognize the sound. Not really a good idea to run it like that in case the compressor crashes or seizes up. If it burns out then it can contaminate the system with acid.

You may want to get a tech to check it.

 

[JBG420]

So I've called a tech and they are scheduled the come Friday - but not sure what good it will do. I cannot get the banging to happen on demand. It is so intermittent. I've tried turning the system off and letting it sit for hours thinking a "cold start" might cause it. Its cycles on at least 10 times this morning and hasn't banged at all. I've searched some YT videos to find a noise that is similar but cant find anything.

Poled around a bit more, changed the filters, and decided to pull the covers off the unit inside. Only thing that I noticed was the "a coil" was hot to the touch. Maybe that's normal?

It was a very distinct banging - 5 to 6 loud metal on metal bangs. Is it possible for something to be broke inside the compressor but only bang around intermittently? Nothing else is loose or in the enclosure obstructing the fans, etc.

 

[yuri]

If it is in heat mode with a heat pump then the inside coil should be warm.

You probably have a scroll compressor which looks like this one in the video. The scrolls may be banging around or there is some other problem.

Usually when the main mounting springs break then it does the banging all the time. Maybe it bangs when it goes into or out of defrost. They can check/simulate that manually if they know what they are doing.

 

[beenthere]

Poled around a bit more, changed the filters, and decided to pull the covers off the unit inside. Only thing that I noticed was the "a coil" was hot to the touch. Maybe that's normal?

That would be normal for a heat pump operating in heat mode. Or recently shut off while it was running in heat mode.

 

[ChantryOntario]

What would it sound like if it was slugging? Would that be a recognizable sound?

 

[JBG420]

You probably have a scroll compressor which looks like this one in the video. The scrolls may be banging around or there is some other problem.

Usually when the main mounting springs break then it does the banging all the time. Maybe it bangs when it goes into or out of defrost.

Actually about 2 years ago the original compressor, which was a scroll compressor, broke and was replaced with a non-scroll compressor (piston?).

Can you explain this defrost thing to me? Is that something that doesnt always run? It's been almost a full 48 hrs and have been running the heat normally and no one has heard it bang again.

 

[yuri]

Watch this video.

Basically your outside unit works like a house refrigerator and removes heat from outside and boosts it and send it inside.

The outdoor coil eventually freezes/frosts up and needs defrosting like your fridge does. Your fridge has a timer and defrosts periodically.