Community Forums

Hikerdogs · 02-08-2012, 05:56 AM

We've been staying in a beautiful Florida State Park for the last few days. Last night when I walked by the rear of the coach I noticed a slight humming sound comming from the control panel section of the basement AC unit. It's a faint noise and you have to get down close to it to be sure that's where it's comming from. The humm can't be heard over the normal noises present during the day. It's only audible when it'sextremely quiet during the dead of night.

The unit seems to heat and cool properly and there are no strange noises comming from it when it's operating. Just to confirm the humm is actually from the AC unit I flipped off the breakers for the #1 and #2 compressors. When they were off there was no noise.

Has anyone else heard this humm comming from their AC unit. Is it normal or something I should be looking into?

Wizard · 02-08-2012, 06:47 AM

I've noticed that on mine before but usually stops when it cycles again. Probably a relay or solenoid not making a good contact. I plan on pulling mine before long for fan noise and will investigate at that time.

You can get to the relays without pulling the unit. Lift outer door/grill. Remove the electrical box cover on the left side and you may be able to check a little closer. Sometime the relays can be cleaned but many are sealed and would have to be replaced.

Won't hurt anything unless it gets worse but if your like me it can be annoying.

swyates · 02-14-2012, 05:24 PM

I've noticed on mine that if you turn off the 12V from the control board, you can hear a relay clicking. When you reapply the 12V, it clicks again. I think it may be the reversing valve. It could be the source of the humming. I believe this is normal.
You can look at the control board and there are LEDs that show the status of the control board. The information on the control board can be found at their web site:
Airxcel | RV Products Tech Info

Martind4 · 02-14-2012, 09:10 PM

We had that same buzzing sound coming from one of the relays on the printed circuit board. Eventually the system failed and I followed the troubleshooting guide to a point where I had to call RVP.

The tech took about 30 seconds to tell me I needed a new circuit board and gave me the updated part number. Lazy Days had one in stock so we were back in business in a matter of hours. Replacing the circuit board was not difficult, just took my time and followed the directions. The unit has been working great ever since.