A/C Tripping breaker

[Griffin_sride]

What could cause the A/C to trip the breaker after it's been running for a while? Sometimes it trips it's own 20amp and sometimes it'll trip it's 20amp along with the main 30amp. It'll only do it when it's hot outside and the unit is really having to work. I've cleaned the coils throughly and they're spotless as well as the return air filter. The unit is 14 years old and I'm just wondering if age and wear will cause the A/C to draw more amps? I've had nothing else in the RV running and it doesn't matter if I'm on generator or shore power it will still trip. When it's cooler or at night it will run just fine.

2000 Fleewood Expedition 36t with 30 amp service.

[Ozlander]

I wouldn't switch capacitors. The others are just as old.
I'd just buy a couple of new ones. They are old enough that they need to be replaced anyway.

[Ivylog]

Sounds like it's the starting amps when the unit is hot that's tripping the breakers. Now that we know you have two units, switch the capacitors between the two units or just add boosting hard start capacitors.

[enblethen]

Pull the cover off the capacitor housing under the shroud and look for burnt wires.
Look closely at both capacitors for any swelling.
Use a good insulated screw driver to go across capacitor terminals to discharge them. Make sure you disconnect from any 120 volt source.

[Griffin_sride]

Oh also everyone I'm really not looking at low voltage overall because the rear ac which is the exact size never trips the breaker. I've also already checked all the connections for loose wires.

[Griffin_sride]

Thanks for the suggestions everyone. I put a meter on the unit and after a few minutes of running after the compressor came on I saw a reading of 13.35amps. I turned fridge on gas and made sure everything else was off and checked main 30amp breaker draw and the reading was exactly the same at 13.35amps. Now I didn't get out there until 6:00pm and the weather had cooled off some but still in the low 90's. I let it run for about two hours with the thermostat set on 60 so it would not cycle and rechecked. 13.65amps. Where in the hell am I picking up over 6 amps from to trip the breaker?????? I noticed when the compressor started up that the meter had a spike in the 41 amp range but it's a cheap little meter without min/max recall capability so I'm not sure how accurate it was. Does anyone know what the peak draw at compressor start up should be?? Does anyone think the start capacitor could be just weak but still working some?? When it heats up in the hottest part of the day and the compressor cycles the start up draw is what's doing it due to a weak but still functioning capacitor?? I took the cover off and the capacitor looks fine. No corrosion, leaking, or bulging at all. I did pull what looked like factory insulation tape off the cover so I'm assuming it's original.

I'm at a loss that it lines out under 14 amps and will kick the 20 amp and sometimes the 30 amp breaker. ??????

[dougrainer]

road-runner wrote:

Capacitors START the motor and the compressor. They are not needed/used once the compressor is running. IF the system is tripping the 30 amp also, that points to a defective compressor. The compressor starts and slowly the amp draw rises until it goes over 20 amps. You need to check the amp draw of the compressor as it is running, and monitor for 30 minutes. IF it is over 15 amps, it is defective.

Correct - they help start the motor. They are not being used after that but they are always in the circuit so if one were to short while the AC is running, it will stop everything.
The cap is not removed from the circuit once the motor starts, it just isn't necessary any more. It has to stay in the circuit to be charged again.

I don't understand these explanations. My RVP/Coleman air conditioner has a START capacitor and a RUN capacitor. I expect that all compressor-based air conditioners have the run capacitor and most have the start capacitor. The RVP wiring diagram for mine clearly shows that the start capacitor is removed from the circuit by the start relay, while the run capacitor is in the circuit all of the time. The service manual text also explicitly states this. I know from first-hand experience with other motor-driven devices that when the RUN capacitor fails the motor will draw more current and often pop a breaker. The purpose of the run capacitor is "to give the motors high starting torque and maintain high power factor during running" (quoted from RVP/Coleman service manual). Without the power factor correction the motor has to draw more current to pull its operating power from the power source.

You are correct. I should have explained fully. IF the Motor capacitor was BAD, it would not start the motor. But, once the motor is started, it stays in the loop. Doug

[wa8yxm]

There are several causes of that.. When it happened to me I took the advice of the singer and went "Up On The Roof". Only that's as far as I got in that song.

Took the outer cover off
Took the condenser cover off
Looked in and said "YUCK"
Grabed the soft brush and the air jet (Hooked to the compressor down below) and made like Gabriel and BLEW (Dirt out of the condenser)

When I got done I blue the crud out of everythnig else crudded up.

Restored covers
Went back inside
Turned it back on
Thatr was like April or May (Forget which) it's still running.

[road-runner]

Capacitors START the motor and the compressor. They are not needed/used once the compressor is running. IF the system is tripping the 30 amp also, that points to a defective compressor. The compressor starts and slowly the amp draw rises until it goes over 20 amps. You need to check the amp draw of the compressor as it is running, and monitor for 30 minutes. IF it is over 15 amps, it is defective.

Correct - they help start the motor. They are not being used after that but they are always in the circuit so if one were to short while the AC is running, it will stop everything.
The cap is not removed from the circuit once the motor starts, it just isn't necessary any more. It has to stay in the circuit to be charged again.

I don't understand these explanations. My RVP/Coleman air conditioner has a START capacitor and a RUN capacitor. I expect that all compressor-based air conditioners have the run capacitor and most have the start capacitor. The RVP wiring diagram for mine clearly shows that the start capacitor is removed from the circuit by the start relay, while the run capacitor is in the circuit all of the time. The service manual text also explicitly states this. I know from first-hand experience with other motor-driven devices that when the RUN capacitor fails the motor will draw more current and often pop a breaker. The purpose of the run capacitor is "to give the motors high starting torque and maintain high power factor during running" (quoted from RVP/Coleman service manual). Without the power factor correction the motor has to draw more current to pull its operating power from the power source.

[dougrainer]

parkmanaa wrote:
How long has it been since you cleaned the coils on this old guy?
Dirty coils cause high apreage draw which in turn causes breakers to
heat up and trip.
Cheapest place to start since you should be able to do this yourself.

His posted stated that he has done this already. Doug

[parkmanaa]

How long has it been since you cleaned the coils on this old guy?
Dirty coils cause high apreage draw which in turn causes breakers to
heat up and trip.
Cheapest place to start since you should be able to do this yourself.

[ScottG]

OP, check the tops of the cap(s) - they're about the size of a roll of half dollars or quarters. If they appear to be popped loose or any material is coming out of them, they are bad.
It costs nothing to do and is a cheap fix.

Here's what the failed cap in my AC looked like. Notice how the base looks canted and corroded (sorry for the blurry pic).

[dougrainer]

ScottG wrote:

dougrainer wrote:
Capacitors START the motor and the compressor. They are not needed/used once the compressor is running. IF the system is tripping the 30 amp also, that points to a defective compressor. The compressor starts and slowly the amp draw rises until it goes over 20 amps. You need to check the amp draw of the compressor as it is running, and monitor for 30 minutes. IF it is over 15 amps, it is defective. Doug

Correct - they help start the motor. They are not being used after that but they are always in the circuit so if one were to short while the AC is running, it will stop everything.
The cap is not removed from the circuit once the motor starts, it just isn't necessary any more. It has to stay in the circuit to be charged again.

Possible, BUT, I have been repairing RV AC units for 36 years and have NEVER seen such a problem. Doug

[ScottG]

dougrainer wrote:
Capacitors START the motor and the compressor. They are not needed/used once the compressor is running. IF the system is tripping the 30 amp also, that points to a defective compressor. The compressor starts and slowly the amp draw rises until it goes over 20 amps. You need to check the amp draw of the compressor as it is running, and monitor for 30 minutes. IF it is over 15 amps, it is defective. Doug

Correct - they help start the motor. They are not being used after that but they are always in the circuit so if one were to short while the AC is running, it will stop everything.
The cap is not removed from the circuit once the motor starts, it just isn't necessary any more. It has to stay in the circuit to be charged again.

[Old-Biscuit]

Happens on shore power AND on generator so rule out low voltage issues (unless generator has voltage issues)

A/C compressor!

But what the heck...you got 14 yrs out of it.