Air Conditioner failure - any ideas where to look

[switz]

Last night the 15K BTU air conditioner compressor quit while the inside fan continued to run. Today after a several hour drive in 95+ degree weather (any icing would have melted) we tried again. (2014 Classic built January 2014 with 50 amp power connection)

The unit fan would start and after a about 15 seconds the compressor would start and would run about 40 seconds and then quit. We tried with or without the other air conditioner running with no impact on this issue. On the Surge Gard I would see zero amps until the unit was energized and the fan would draw a spike of six amps dropping back to two or three amps. When the compressor started, the current would jump to fourteen or fifteen amps and then drop back to three when the compressor stopped.

There were no issues with the 13.5K BTU secondary air conditioner which is on the other power leg.

I removed the inside air conditioner air filters from both units and washed them. Very little dirt accumulation and the water was not really dirty. Unit ran for a few minutes and had several successful cycles. Then returned to maybe a ten second run before quitting.

One chap here mentioned the "phantom Fantastic Fan" syndrome. Fantastic would send a couple of resistors for the fan wiring and the air conditioners would work fine.

Since the compressor starts, the starting capacitor is probably okay, but perhaps the run capacitor is failing.

I would appreciate any other ideas to check out to resolve this issue. The upcoming long weekend precludes finding service here in Farmington, NM at the International Rally.

[ShinyPete]

Switz-

I may not help with your specific issue, as we experienced a similar failure but not with exactly the same details.............yet I'll share in case.

Our 15k Penguin II quit in Nov 2014 (about a year old) and had to be replaced under warranty. It's operating parameters @ failure where that the fan would come on as normal (cool or heat pump), and the compressor would kick on and run...........but it would never cool. Also, the compressor "sounded" weak. I discovered one night camping that the unit was running for a long time and no joy on cooling the coach. Compressor failure = replacement unit.

Just this week I experienced a control board failure (a long story for another thread when I get time). This led to no HVAC operation of any kind, not even the furnace. My only suggestion is perhaps the control board in that unit is going flaky? It kind of sounds like the unit performs fine when it runs, but the timing cycles or demands are off?

Our unit is a Dometic 651816C, and the control board it required was a Dometic 3312227.000 that I swapped myself without too much drama (drain those capacitors before inserting fingers).

Hope this is some help.......

[andrew_uk]

I would defiantly change all the cap's they are cheep enough on e-bay....

[moosetags]

We had a similar air conditioning failure about two years ago on our 2012 Flying Cloud 23FB. The A/C unit fan would blow buy the compressor would not kick on. We had it looked at and the compressor had failed. We had bought the 23FB used. Even though we had purchased the remaining warranty from Airstream, as the appliances are covered only by the manufacturer's warranty and Dometic's warranty only applies to the original owner. So, we had to eat a new air conditioner on an 18 month old Airstream.

Brian

[lsbrodsky]

This is my third summer on the forum and it strikes me that I am reading about more failures this summer than the previous two summers. Whether capacitors or compressors, a) I wonder if my impression is true b) I wonder whether it is attributable to low voltage in campgrounds with heavy AC use?

Larry

[lewster]

Lou,

You should still be covered under your original Dometic warranty. Locate a Dometic certified tech and gave them go over the unit. There are too many possibilities to list for trouble shooting.

If all else fails, call Dometic factory tech support and run the problem past them.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

[damonbeals]

If your at the International Rally in Farmington. Then go find Howard, he will help you diag the issue. He is over the Technical Committee and writes the monthly article in the Blue Beret. He has also replaced 10 bad 20Amp circuit breaker at the Rally.

Damon
#4827

[B00merang]

Regrettably I may have the answer since my 2010 20ft FCC is just being fixed.....same symptoms....temp between 94-99 in north Florida...and muggy as all get out: the Circuit board!!!!
You need to replace the circuit board in all probability. In the meantime, you can do what my 6- yr old and I did: buy a 20" fan at Walmart and have it blow on you. Safe travel. Jon

[drboyd]

If that were a residential unit, it would 99.99% be the condenser fan.

[gr.austin]

This certainly sounds like a high pressure failure. This can be caused by:

1. Blocked/dirty condenser coil
2. Failed condenser fan motor
3. Failed condenser fan capacitor
4. Failed condenser fan relay
5. Failed t'stat
6. Failed A/C short cycle circuit board
7. Too much refrigerant
8. Failed compressor capacitor
8. Loose wire nut connecting A/C unit to 12awg R/V wiring
9. Failed internal thermal overload. Compressor replacement required.
10.Locked Compressor shaft. Compressor replacement required.

Good news, it is more than likely NOT caused by:

1. Low refrigerant charge/leak in system
2. dirty/blocked Indoor coil
3. Low Voltage
4. Wrong Wire Size

Check this out in this order:

1. Does condenser fan run when compressor is trying to start?
2. Is condenser coil clear of all debris and clean?
3. Is there voltage on the compressor when it is trying to start? If you are not comfortable getting this voltage at the compressor (may not be easy to get to) don't attempt it you make need a professional.

If the first two are good and there is voltage on the compressor then the compressor capacitor is a highly suspect failed part.

If there is no voltage on the compressor then check the voltage before the relay.

Give me a private massage and I'll walk you through the rest.

Gary

[pappy19]

I had the exact same problem and a new mother board finally fix it. That was 2 years ago. On really hot days I always leave the cabinet door open that covers the main breaker box. Seems when the breaker box gets hot, the breaker that runs the AC breaks.

[Fly at Night]

Sorry, can't offer any help, but I had a slight problem too. (Is okay now). Hope your issues work-out because a summer Airstream w/o a/c is a pretty miserable experience.