A/C Woes

[Belttech]

Last week we stayed at Yosemite RV Resort...
Like most of the western hemisphere it was a little warm. After returning from a day visiting Yosemite, two of three AC's were not working (running, but not cold). The bedroom one was fine but the two front were not, pulling about six amps each. So today I ran them, first on the generator and then 50a shore power. They all are now pulling 20a each. Before, they would run at around 12a each.
They are the originals to my 2009 Dynasty, 1500btu each. Not the best of times to purchase new units... I think it is odd that all three are acting up.
Any thoughts on what I'm experiencing would be appreciated

[jacwjames]

There have been several recent posts on AC units not cooling recently. You may try doing a search. Here is a relevant on
https://www.irv2.com/forums/f115/duo...ng-496426.html
There are a couple documents I posted in this thread, in particular a trouble shooting guide.

First thing to try is a good cleaning of the condenser.

But from what it sounds like the start capacitor may have failed.

Do you have the model number of the AC units. If so you can go to the Edometic website to look up parts.

https://www.edometic.com/allusr/sp.n...&searchorder=4

[K7JV]

Good morning, Belttech

Wow, I'm so sorry! First off, I'm not very informed on these units, but I have had a number of "odd" experiences with ours. Actually, the front and middle units on our '06 Dynasty failed in the first two years and were replaced, but knock on wood, they've been good, since. But they do, occasionally, mis-behave and exhibit current draws that I don't expect to see.

It is odd that all three have chosen the same time to begin working differently. Things like freon levels or start/run capacitor failures shouldn't happen at the same time, unless some other factor is causing the common problem.

The three common ties between two or all three of them would be the thermostat control circuits, the 120 VAC supply, and any environmental extremes not previously encountered.

I'm not sure what to tell you to look for on the thermostats. There is a reset procedure for them that can be found in your documentation or on-line. You might give that a try.

As for the AC supply, you indicated that there is no difference whether you are on shore power or the generator. Assuming your transfer switch is operating properly when you run the generator (the generator is probably the "preferred" source and should switch to that once it is "stable", even if still plugged into shore power), that should rule out anything outboard of the transfer switch. But low AC voltage will result in high running currents on most all AC motors including your heat pumps. You might try plugging a simple voltage tester or a volt meter into one of your outlets while the AC's are trying to operate and see what the voltage looks like. You will probably have outlets in the front part of your coach that will be on one leg of your AC panel along with one or two of the heat pumps and outlets in the rear of your coach that will be on the same leg as the other heat pump(s). You can look at your breaker panel and determine which leg each pump is on, and which leg each of our outlet circuits is on. The even numbered breaker positions will be on one leg and the odd numbered breaker positions wil be on the other leg. The odd numbered breakers should be on leg A and the even ones on leg B.

As for the environmental factor, if you haven't already, you might shut all three of them down, perhaps even doing it by shutting off each of the three circuit breakers, and let them sit for a couple of hours. That will allow each of the units to reach a stable temperature and all of the refrigerant to reach its normal "resting" state. Then power them back up and see if they perform any differently.

I'll be interested to see how you make out with this. When multiple things act up at the same time, it is easy to take a wrong turn and find problems that may not really be problems and miss the true culprit. Good luck to you!!! We have had crazy events like you are experiencing, as have probably most of us on this forum.

[YC1]

Just a thought and may be way off but have you checked your battery voltages and connnections.

The control boards rely on a good clean source and if that went fubar for a few seconds while say, both AC's were starting up it could lead to weird problems.

I really don't know why the didn't simply design their own 12 volt supplies. 110 volts is at the air conditioners already.

[Ivylog]

Corrosion on the phone type control cables is a frequent problem... unplugging multiple times is usually enough to clean. Start with the ones in the return air areas inside. There’s also one on the control board up top on each unit. Helps to have all three zones on cool or individual ones off if not needed.

[Outbound]

I'm surprised you can run (3) a/c units, refrigerator etc on 50 amp power?

[twinboat]

Originally Posted by Outbound

I'm surprised you can run (3) a/c units, refrigerator etc on 50 amp power?

Why would you be surprised ?

120/240, 50 amp service is split to two 120 volt 50 amp legs in the RV breaker box.

Two ACs on one leg and one AC on the other.

[Outbound]

I guess I'm getting old, I am thinking start up loads every time they cycle, is there a lock out to keep them from starting at same time?

[Boe]

Are you sure you can run 3 at one time? My understanding is only 2 will. But back to finding out if problem with units. Just run the first one. If works it’s fine. It should pull 20 amp. If works turn off and turn on second one and so forth. If they all works I don’t think anything is wrong unless I missed something in the post 2 running will pull 40 amp not sure there is enough to kick the 3 rd one on but I could be wrong Some people think all 3 will run but In reality only fan is on with the 3 rd one It’s because it doesn’t have enough power to pull the 3 compressor on most people are just feeling the cold air in the duct work and fan is running Good luck

[jacwjames]

My AC don't pull 20 amps when running. Even if they did running three is only 60 amp. Refrigerator isn't that much so I don't see it bumping over 80 even with other small loads. A 50 amp circuit can handle that.

[Outbound]

How about when you add electric hot water, micro etc.

[vito.a]

First I'd like to clear up a misconception. You can easily operate all three A/C systems on either generator, or shore power. Monaco installed three A/C systems on 42' and longer coaches along with a 10k generator. (Signatures and Marquis receive a 12k generator.)

The A/C units are wired through a 20 amp circuit. The maximum amount of current they can pull is 20 amps. Anything more and the breaker will trip. However, most Dometic A/C units use about 12-13 amps when running. They are designed to stagger startup with the fan starting first and then the compressor. A thermostat assigned to two A/C systems will also stagger the start of each system.
Okay, after explaining all this if your coach also came with an electric clothes dryer it will share the circuit with one of the A/C systems and only one can operate; either the dryer or the A/C.

Belttech, I assume your 2009 Dynasty has heat pumps? This generation of Dometic Heat pumps normally runs in the heat pump mode and uses a reversing valve to run in cooling mode. These reversing valves will fail. If your units were blowing warm air then the reversing valve was not working correctly. The reversing valve coil is easily replaced. just two wires.
The other common issue is the starting capacitors covered above.

If you decide to replace one or more of your A/C units you will need to understand the new units are set up to use the new Comfort Control II thermostat. You can either purchase a retrofit control board or update to the newer thermostat. However, the new CC2 thermostat will not operate the older units so its all or nothing.

Hope this helps!

[Belttech]

Thanks everyone for your replies !
I went ahead and replaced all three ac units, with Dometic Penguin II units.

On the old 5 button thermostat was a zone 4 which controlled the bathroom heat exchanger. Now on the new cc2 thermostat there are only 3 zones. Just wondering how to program the new thermostat to add the 4th zone ?
Anyone have any experience with this ?
Thanks for your thoughts !

[96 Wideglide]

Originally Posted by Outbound

How about when you add electric hot water, micro etc.

My 10KW gen will run all three heat pumps, fridge, AH on electric, microwave, and it puts out less wattage that a 'good' 50A shore connection.