PDA

View Full Version : Rumbling noise when A/C condenser starts


DanA
12-31-2006, 03:52 PM
I have a Bryant 5 ton heat pump system 9 1/2 years old. I noticed this year when I turn on the A/C after it being off for a while (1 - 2 weeks), that it has a loud rumbling noise when it first starts up. It sounds like the whole condensor is shaking. Never happened till this year. If it cycles off then on it doesn't happen. Only happens when it's been off for a long time.

Yea, we use A/C at times in the winter.

Any ideas?

Dan
Palm Harbor, FL
mcginkleschmidt
12-31-2006, 03:56 PM
When I read this post I could swear I was having a deja vu moment!
MB1211
12-31-2006, 04:03 PM
No, it's just an echo.
star882
12-31-2006, 07:28 PM
I have seen this happen on a Brysch scroll compressor used in a CPU cooler. What happens is that the magnet inside the compressor is shaking as it tries to "lock" onto the moving magnetic field from the coils. Before it locks, it vibrates a lot. Once it locks, the shaking stops.

In your case, liquid refrigerant might be migrating into the compressor and making startup more difficult. Is there a crankcase heater installed? Is it working correctly? It might also be a degrading capacitor or something loosening up.
DanA
01-01-2007, 01:00 PM
Your explanation sounds logical. I don't believe I have a crankcase heater installed. Is it worth it to have one? Will the occasional shaking cause a long term problem? If I need a heater, can it be i nstalled by DIY or get a professional. Is it worth installing it on a ten year compressor.

Dan
star882
01-01-2007, 04:08 PM
On something that old, it's about time to upgrade. Just check for loose bolts and simple-to-fix problems, then just use it until it breaks.
Shophound
01-01-2007, 06:30 PM
Your explanation sounds logical. I don't believe I have a crankcase heater installed. Is it worth it to have one? Will the occasional shaking cause a long term problem? If I need a heater, can it be i nstalled by DIY or get a professional. Is it worth installing it on a ten year compressor.

Dan

If you're not yet ready to replace your system, a crankcase heater isn't that expensive, but should be installed by a pro. Sounds like you're experiencing migration...a scroll is a bit more tolerant of it but it isn't bulletproof...I'd go for it.