AC humming.....
- Thread starter rvnutts
- Start date
wdk450
Well-known member
The refrigerant/compressor system is the big ticket item in an RV rooftop air conditioner. You can find a new fan motor, new fan capacitor, new fan blades on E-Bay or RV parts suppliers. What make and model of AC do you have? The fan motor and capacitor would cost about $135
Maybe all you need to do is to oil the fan motor shaft ends and make sure the fan motor shaft turns freely. If the fan doesn't run, the compressor doesn't get any cooling airflow, it overheats, and the compressor has an overheat thermal switch mounted to it that will turn it off too. If fan motor won't work with just oiling, the fan capacitor would be next on my list, but if it is hot outside and you want to get the AC going ASAP I would either get a mobile RV repairer out with the parts on hand, or order the fan motor and fan capacitor overnight shipping. I did a Google search for the fan motor for my Brisk Air II and got prices from $88 to $112. The capacitor on mine is a split model having both the compressor and fan capacitors in one case. The capacitor prices on a Google search were around $35. The entire AC top unit (minus the ductwork connector or non-ducted air louvers/controls) was at $535 on the same Google searches.
Good luck!!!
Maybe all you need to do is to oil the fan motor shaft ends and make sure the fan motor shaft turns freely. If the fan doesn't run, the compressor doesn't get any cooling airflow, it overheats, and the compressor has an overheat thermal switch mounted to it that will turn it off too. If fan motor won't work with just oiling, the fan capacitor would be next on my list, but if it is hot outside and you want to get the AC going ASAP I would either get a mobile RV repairer out with the parts on hand, or order the fan motor and fan capacitor overnight shipping. I did a Google search for the fan motor for my Brisk Air II and got prices from $88 to $112. The capacitor on mine is a split model having both the compressor and fan capacitors in one case. The capacitor prices on a Google search were around $35. The entire AC top unit (minus the ductwork connector or non-ducted air louvers/controls) was at $535 on the same Google searches.
Good luck!!!
Flooringit
Well-known member
I know on the brisk 2 units in order to acess some bolts to change fan motor you have to take the ac unit completely off to access the bolts from the bottom. What a bummer they did that. Was prolly done on purpose to get you to buy more parts. So if you have a brisk your gonna need a new seal also. I had a ac just blow hot air so I bought a new unit tried to keep the motor and caps for spares but once I figured out the fan bolts were on bottom I said screw it. I’ll buy a whole new unit if I got to pull it
Thanks for all the replies. We had a mobile repair man come out here in Branson. Was hoping for the best but got the worst. We just need a need a new unit. But we decided to wsit till next year to replace. Our bedroom unit and fan kept us cool. For fall campi g we will be fine. DH said no use starting a new warranty when going into storage for the winter.
wdk450
Well-known member
Considering that the rated current is about 12 amps, and the branch circuit breaker is 20 amps, YES repeatedly pulling 45 amps would be indicative of a bad compressor.
jerryjay11
Well-known member
Actually the starting amps of a compressor can be 5 times that of the run amps. Maybe your compressor is bad, but that amperage alone isn't enough to convince me. A defective start control relay or capacitor would give you the same results. The reason it shows 45-55 amps every few seconds is because of the overload device (acts as auto reset circuit breaker) is tripping and resetting.
The capacitor can be checked with a capacitor tester or multimeter (Google it). I prefer using the tester for accurate microfarad reading. When start relays fail they usually rattle. Both components are relatively inexpensive if you want to give it a try before spending big bucks on a new AC unit.
The capacitor can be checked with a capacitor tester or multimeter (Google it). I prefer using the tester for accurate microfarad reading. When start relays fail they usually rattle. Both components are relatively inexpensive if you want to give it a try before spending big bucks on a new AC unit.
CarterKraft
Well-known member
I would bet my big Mac meal it's the capacitor. I went through this at the river this year. I could spin the fan motor by hand and start the AC and it would run but the compressor would not start.
During the night when the failure started the fan was on high, not auto and the compressor wouldn't start but the fan did stay running.
A new capacitor made it as good as new.
On my 15k Brisk Air II I used a Amrad 60/5X370/440 American made dual run cap.
https://www.amazon.com/AMRAD-ENGIN...ocphy=9027240&hvtargid=pla-378359102040&psc=1AMRAD USA2220B
Sent from my SM-G950U using Tapatalk
During the night when the failure started the fan was on high, not auto and the compressor wouldn't start but the fan did stay running.
A new capacitor made it as good as new.
On my 15k Brisk Air II I used a Amrad 60/5X370/440 American made dual run cap.
https://www.amazon.com/AMRAD-ENGIN...ocphy=9027240&hvtargid=pla-378359102040&psc=1AMRAD USA2220B
Sent from my SM-G950U using Tapatalk
CarterKraft
Well-known member
This is great advice. I would try these parts for sure and if nothing else you will have them as spares for the new unit.
FYI niether a local RV shop or a Camping World had these parts on the shelf.
I got the capacitor at a local HVAC supply house, payed $20 over the Amazon price I linked to.
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jerryjay11
Well-known member
Correct, RV shops/camping world wouldn't carry such an item. It would be HVAC/R, plumbing supply houses as you discovered. It's a cheap fix if it works. I'll keep my fingers crossed for ya.
michaelcuomo
Member
There are basic 5 symptoms which show the AC compressor fails and bad to use.
The compressor doesn’t turn on at all
The system is blowing warm air
The system keeps tripping the circuit breaker
The outside unit shakes when it starts up
The outside condensing unit is making strange noises,
if the amp showing the fluctuation you should change it asap or else the main meter circuit will drop down.
