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Topic: AC capacitor replacement  (Read 382 times) previous topic - next topic

AC capacitor replacement

This spring my rear Dometic Duo Therm AC quit working and I discovered the dual fan/compressor  run capacitor was dead. I replaced it and it worked. This summer it stopped working again. I tested the two remaining capacitors and the little one was showing an open circuit. Ordered a repair kit that included both "start capacitors."  Replaced it this morning and AC now working again.

If one capacitor fails should you replace all of them? Not an AC guy. They are not easy to find and it takes about a week or more to get them.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: AC capacitor replacement

Reply #1 –
Quote from: Realmccoy –
If one capacitor fails should you replace all of them?

The short answer Yes.  If you have spent labor hours to replace one capacitor all you are out is the money for the other capacitor. Said another way I am not going to clime up on the roof and remove the covers to get to the capacitor hiding spot and not replace both. While there check that PTCR and see if it is bad. . (if your unit has one) Capacitors don't have an expiration date on them like milk but as much as our home A/C unit runs in the summer I install new ones every 5 years.

FYI if you don't know what a PTCR is http://www.tiffinrvnetwork.com/crusingator/P/P-090.pdf

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: AC capacitor replacement

Reply #2 –
If you use the cheapest made in China capacitor, expect failure.  If you use a quality capacitor such as MARS or  any made in USA, you can expect them to last a long time.  Sometimes, you can check a PTCR with your nose.  They usually have that burnt electrical stink if bad.
2014 Newell 2020P

Re: AC capacitor replacement

Reply #3 –
It was the PTCR that failed. No smell but showed bad with my multi-tester. And it's really two trips to the roof, once to check and then again to replace. So I've  made five trips to the roof in the process of figuring this out with no prior experience. It can also be momentarily exasperating if you don't remember you turned off the breaker when testing new capacitor.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: AC capacitor replacement

Reply #4 –
Mike, I installed 3 Soft Starts on my A/C's.  I believe they have that PTCR built in them?  Is that correct?  I know they sure weren't anywhere near that $17 you paid!  LOL
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: AC capacitor replacement

Reply #5 –
Quote from: Pamela & Mike –
The short answer Yes.  If you have spent labor hours to replace one capacitor all you are out is the money for the other capacitor. Said another way I am not going to clime up on the roof and remove the covers to get to the capacitor hiding spot and not replace both. While there check that PTCR and see if it is bad. . (if your unit has one) Capacitors don't have an expiration date on them like milk but as much as our home A/C unit runs in the summer I install new ones every 5 years.

FYI if you don't know what a PTCR is http://www.tiffinrvnetwork.com/crusingator/P/P-090.pdf

Mike

Amazon.com: PANDEELS 8333A9021 Capacitor Hard Start Kit - Fit for Coleman...

Amazon.com: Coleman 8333A9021 Hard Start Kit : Automotive

I 100% Agree that time changing start capacitors will save you money and hassle. This is in the tire category and no one wants to be on the side of the road.
Both AC start/run capacitors, generator cooling fan start capacitor too. Do them like smoke detector batteries and they will extend the life of the motors they are starting and reduce stress on your entire electrical system from the excessive loads from these motor starts. This includes generator loads, transfer switches, power reel brushes and commutator damage, plug and sockets wear. Small investment IMO. Adding PTCR great addition
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Re: AC capacitor replacement

Reply #6 –
I think that I still have most of the new capacitors from my roof units.
Free to fair home.
 

Re: AC capacitor replacement

Reply #7 –
Realmccoy stated he had a Dometic/Duo Therm AC, not Coleman.
One of the replies, above, is for a COLEMAN hard start cap.
Are these start caps interchangeable?
Steven
1997 U320 40'  Orlando, FL
"Purple Haze" which will soon be for sale.... !