AC Unit intermittently trips breaker

[Newcsn]

We have 3 15000 BTU AC/Heat pump units on our Dynasty - they appear original, so probably 16 yrs old. One of them - with increasing regularity - will trip its breaker. We reset the breaker & we’re good to go until it decides to have its next hissy fit. It might happen daily, ever other day or once a week - no seeming regularity.

Does this sound like a capacitor? Thanks

[Jim Pratten]

Breakers usually have trip curves that operate quickly on high current such as a short and more slowly when the load exceeds the breaker rating. The mechanism for the slower trip is often a thermal element which can degrade over time. I’d swap breakers with one of the other units and see if the same breaker or same unit trips. That should help you isolate the problem to either the breaker or air conditioning unit. My money is on replacing the breaker. 

[LakeBob]

Yes, sounds like the capacitor is getting weak.   An easy replacement, if you can find the same size.  I've replaced all three on mine and all the dual range capacitors are larger in physical size.  I had to relocate the soft start capacitor off to one side and was able to mount the new larger capacitor in the original space.  

This is the OEM capacitor in the images below.  Forgot to take a picture with the new capacitor in place.  You'll just need a longer sheet metal screw to fasten the strap around the larger capacitor. The black capacitor (hard to see in the picture, below the main capacitor) is the one I needed to move over to the left. 

Or could be a bad circuit breaker as Jim mentioned. 

 

Edited December 17, 2022 by LakeBob
Update

[Jim Pratten]

Agree, could be the cap. Though most often when start/run caps fail, the motor stalls on start and trips out before running. Bad caps usually swell up and, with cylindrical caps, the ends will bulge out. 

[Bandit411]

My front a/c was doing that and I had to change the blower motor. 

[Tom Cherry]

Food for thought.  Your AC’s are getting old.  They are gonna have to be replaced.  If you do them piecemeal, you spend a lot more on the replacement buying modules to carry you over to keep the same thermostat….plus, you spend money having a tech pull out the factory board and put in the replacement….that you buy for $150 or so….You may have three 15K or two 15K and one 13.5 K.  It’s a matter of pay me now or later….plus how much your budget can afford or how long you plan to keep the MH….age, travel bucket list, medical, etc will influence that.  The final thing is your electrical skills as well as the ability to climb on top and do repairs……

a breaker will be less than $50.  If you keep “punishing” a breaker…..it will die.  You may be there already. Whether it will solve a problem with a dying, pulling more current front AC (the one that usually has the most use and dies first) is debatable….  Installing is easy, but you have to be able to do simple electrical work.

a new capacitor on a dying or almost dead unit will probably, unless there is physical damage to the capacitor or unless you have a meter that allows you test, MAYBE last.  Obviously a damaged or will not test capacitor should alleviate the problem….unless the AC is really needing more power.

a LOT of folks purchase the “soft start” conversion.  It is several hundred $$, but there is or was a $100 rebate or discount…..may run through the end of the year.  There is a topic dedicated to that so you can look it up or Google and see if the rebate is still out there.  If the compressor has some wear, you may get a few more years out of it with that….

I am not an expert on “is it the blower or the compressor”….and how do I test or determine that.  You might PM the poster that made that comment.  Yes, we do have blower failures…but they are, my memory, low compared to capacitors….but again….it does happen.

Then…there is a financial decision.  If you plan to upgrade all eventually and inflation is still prevalent next year, some folks will do a major upgrade early as they will pay less now.

Those are the items I would look at.  

I would inspect the capacitor and test it.  If bad, then the soft start might be the best option….but be prepared to change an overworked breaker….again, your skill set and ability to do these things versus a tech comes into play.

Keep us updated as to what you find when troubleshooting and what you do… Good Luck…

 

[Ivan K]

I had that with the center unit when we got the coach. The breaker was getting hot and it stopped after tightening the wire terminals, some were not so tight.

[Jim Pratten]

14 minutes ago, Ivan K said:

The breaker was getting hot and it stopped after tightening the wire terminals, some were not so tight.

Another good point. Shortly after we got our Dynasty, I tightened all the AC and DC power connections that were relatively easy to get to. The majority of screws tightened a quarter turn. A few took half a turn and a few were fully tight. 

[Newcsn]

You guys are awesome - thanks for the “food for thought” (and to potentially spend more $$$ than I want to)! Looks like I’ll proceed in this fashion:

1. Check connections 
2. Switch breakers (replace as needed)
3. Check capacitors (replace as needed)

If none of these resolve the issue, then I have a very weighty $$$ decision to make. 3 15,000 BTU AC units w/ heat pumps & thermostats is no cheap date!

Thanks for all the great feedback!

[MyronTruex]

I rarely suggest "tossing parts" at an electronic issue but often substitution (replacement), is the best option.

Those parts are very common failure items and I would not waste time attempting to test them. Just get the parts, the ptcr might be a good thing to replace as well. You can probably find a "kit" with all the parts.

Your breaker may be getting a bit tired from all of the exercise so you could replace it or swap it into one of the other AC positions just as a test but breakers are not generally high cost devices. 

I agree you are getting to the end of life on the AC units but they may give you several more years if you clean them thoroughly and replace the parts that are suggested.

I would also take the shroud part of the condenser that does the cooling and give it a good cleaning. 

[Ivylog]

I’ll take a AC that uses R22 (123 liquid psi)  over R410-A  (200 psi) any day. The ACs on my 04 Dynasty are original so 19 years old. Yes I’ve had to replace some capacitors and shim the blower motor up on one until that didn’t work…had to move the squirrel cage blower on the shaft because it was rubbing on the side.

[bandmmorris]

I have had that problem a couple of time and each time I replaced the breaker and solved the problem. Breakers can get weak over time and not carry the load they were designed for.

[jacwjames]

20 hours ago, Bandit411 said:

My front a/c was doing that and I had to change the blower motor. 

Mine was occasionally kick the breaker so I started watching the EMS load meter and saw it pulling high amps on startup.  It also was louder.  So I check the motor and it was almost seized, I could barely turn it by hand.  So I took it out, when I did I also found the rubber isolation mounts were wore out and it let the motor sit lower letting the fan blade hit sheet metal occasionally.  So I found a replacement motor on line for $125 and installed.  This fixed the problem and the AC was quieter.   This was in 2015. 

Last year my rear AC started making a racket, so I checked and the isolation mounts were bad, so while I was tearing into it I was going to change the motor.  Could not find one anywhere.  So I decided to just bite the bullet and change both AC's  Bought two new ones from PPL and a new Microair thermostat.  Cost ~$3000.  I recently checked on the price of an AC and the price has double since I bought last year. 

[Georgia Mike]

If you are looking for a capacitor I got a spare for my Penguins at this surplus place. 
https://surpluscityliquidators.com/products/5515-mfd-440-vac-dual-run-capacitor.html

[BrokenArrow1244]

I have had a lot of problems that caused me to get borderline with replacement, but,,, Take the time to get the components checked even if you need to buy meters to run the tests on the capacitors. Also do some deep reading from some of the specifics from this forum. It also is a good idea to pay close attention to the failure. I had the heat pump coming on and thought the a/c was blowing hot air. I found from the forum that the "failsafe " is to activate the heat so we do not freeze to death.  That was the failed part on the heat pump solenoid.

Since it does reset and operate, it has the ability to work.

Also, circuit breakers can get weak too.

good luck.

[VinceB]

In addition to all the other great suggestions I suggest that you check the foam rubber gaskets on the underside of the shroud. Over time they go flat.

On my Dometics there is foam that creates seperate chambers in the unit: one for each coil. Bouncing down the road along with heat makes the gaskets flatten out becoming ineffective. The foam keeps the air for each coil from mixing with the other - they also keep the air moving in the right directions.  If these 2 air masses are allowed to mix short cycling can result which takes a toll on the breaker as well as the compressor motor. 

I had a unit that was occasionaly tripping its breaker.  It wasn't blowing real cold either. I also noticed that the compressor was cycling - probably had too high of pressure in one side of the system. After some trouble shooting, I found nothing. Sitting there just staring at the unit, I saw flat gaskets in the shroud - an Ah Ha! moment. Installed new gaskets and breaker which solved the problems.

Back in the day new shrouds came with the gaskets pre-installed - no more. There are gasket kits available but are ridiculous in price.  I went to H Depot and bought some window AC foam on a roll - self adhesive on one side - just a few dollars - IIRC 3/4" thick. The material seems to last just as long as the OEM.

The challenge was lining the foam up on the underside of the shroud.  So I just figured out where they needed to go and stuck them on the coils and other sheet metal where needed. It was not rocket surgery.

I now pay attention to how often the compressors cycle and the output of each unit taking into consideration ambient temperatures - more art than science.  When I hear short cycling or I detect that a unit is under performing I know it is time to replace the gaskets.  I've had to do it 3x over the years. I replaced only the 1 breaker in 22 years because I didn't replace the gaskets in time.

Bottom line: this is the first thing I check when a breaker trips or a unit is not performing.

[hitechpete]

On 12/17/2022 at 4:17 PM, Newcsn said:

We have 3 15000 BTU AC/Heat pump units on our Dynasty - they appear original, so probably 16 yrs old. One of them - with increasing regularity - will trip its breaker. We reset the breaker & we’re good to go until it decides to have its next hissy fit. It might happen daily, ever other day or once a week - no seeming regularity.

Does this sound like a capacitor? Thanks

I had the same problem with one on my 2000 Diplomat, try lubricating the shaft bearings on the A/C fan, it fixed mine.

[Newcsn]

Thank you all for your input - this group is great! Will provide an update once I have a chance to work on it. Gonna try connections & breker first and see what happens. But, won’t have a chance to run it through its paces until March. Thanks as always!