Air Conditioner in toy hauler keeps drawing more amps

[stacaz822]

Anyone have any reason why a roof mounted A/C unit would draw more amps than normal? I have had it for over two years (its on the camper that I bought used, was built in 2009), and it worked great from my house when plugged into a 30amp outlet, and also worked great with my Yamaha EF3000SEB inverter generator. Lately, it has been popping the house circuit breaker, as well as just shutting off when camping on the genny. No other loads on those circuits. Thanks! I have background in EE and other engineering fields, I cleaned the filter, it blows fine, no air restriction. Maybe a start or run capacitor? It blows great cold air still (while it's on!)

[stacaz822]

I replaced the (45+5) CAP for about $15. I checked the evaporator and condenser fins and all was very clean. Blowing 60 degree air now, while outside temp is 103 in PHX. Running volts inside the camper while A/C is on full blast are back up to 122 volts, where it should be! Thanks, Guys, as always!!

[stacaz822]

Well, I think I found the culprit, a Start/Run Cap over 10 years old.

https://photos.google.com/album/AF1QipMco9_SO150ddEYmeSp06Yy0FVbJ1f14Y5E7vDz

Ugh! I hate how you have to post photos here!!! Why can't you just copy and paste!!

[wa8yxm]

Two reasons. Most common. Condenser needs cleaning
Least common Compressor going going and soon to be gone.

If it is the condenser clogged. then it will start out normal and climb over a period of minutes.

If it's the compressor it normally starts high

[Chris_Bryant]

Clean the coils.

[stacaz822]

SidecarFlip wrote:
Just BEFORE you stick your fingers in there... short across the can lugs to be sure the can is totally discharged.... But then I assume you already know that..

They don't all have dropping resistors.

Heehee, I learned that at 5 years old. I was born with a soldering iron in my hands! At four years old, I grabbed the hot end in my dad's garage, and after that, I was expert with it, lol. As an aerospace test engineer, I know about large CAPS storing HIGH voltage for minutes, or even hours!

[SidecarFlip]

Just BEFORE you stick your fingers in there... short across the can lugs to be sure the can is totally discharged.... But then I assume you already know that..

They don't all have dropping resistors.

[Wild_Bill_888]

The filter protects the cooling heat exchanger from dirt dust pollen etc., but there is an outside air exchanger that dumps the heat, that is less well protected. As air flow is restricted, temperature and pressure increases loading the compressor more.

The most effective cleaning is with a medium velocity flow of water in the reverse direction of air flow. A high velocity flow will bend the fins over and plug the core.

[stacaz822]

OK, I see will try this. Have to climb on top and take the top off, and that little door to change the RUN CAP... THANKS!

https://www.youtube.com/watch?v=Ty_ou_TW5EM

I have done this several times on my home A/c units, mainly for the fan start cap...

[ScottG]

Replace the start and run caps - they are considered a wear item on AC's and should be replace periodically (this includes home central units).
Yours are up top.

[stacaz822]

cougar28 wrote:
Check your run capacitor they reduce your running amps.

Do you happen to know if it's accessible from below, or above?

[cougar28]

Check your run capacitor they reduce your running amps.

[azdryheat]

Sounds like you have a new A/C in your future.