Air Conditioners and Really Hot Weather

[PCarnathan]

We have a 2009 Mandalay 43A with three rooftop air conditioners. While at the Colorado River a few weeks ago with outside temperatures exceeding 110 degrees, the air conditioners started tripping their individual breakers. I could reset the breakers, but within twenty minutes or so they'd trip again. Eventually, one of the air conditioners stopped working altogether until very late at night.

Each air conditioner is pulling around 14 amps (I checked). Here's the kicker: This happens while plugged into 50-amp service at the campground as well as running on the 10,000-watt Onan diesel generator.

The RV tech is telling me "... it's just too hot." Well, shoot, I guess I shouldn't run the air conditioners when it's hot?!

Do you have any thoughts?

Pat in Menifee, CA

[dougrainer]

DC&MC wrote:
He said he had a Mandalay, not a Tiffin

I KNOW that. I was relating what Tiffin did to fix this type problem. Doug

[DC_MC]

He said he had a Mandalay, not a Tiffin

[Y-Guy]

Pat, sounds like you've gotten some great advice already. I may have missed this, but we found that in extreme heat if we bring in our slides it reduces the volume of air to cool. Camping in 118° in Southern Utah one year it's what saved us from roasting. Just a thought for you.

[PCarnathan]

Thanks for the multiple replies. No, I don't run the generator while plugged into shore power. The air conditioners have been professionally cleaned. They're all on their own individual breakers, I don't know the rating of the breakers because the coach is at the shop having some minor work performed.

Folks have suggested tightening the breakers - That's a possibility I'll check when I get the rig back. Also, the breaker and fuse panel are located under the master bed. Not quite over the engine; but pretty close. Due to an engine thermostat issue, the back bathroom and master bedroom got very, very warm, so if the breakers are heat-actuated that could be an issue, too. I'm thinking of putting a pair of thermostatically-actuated fans under the bed to run some ambient air across the back of the circuit panel. One pushing, one pulling.

We're heading back to the Colorado River (Park Moabi) this Thursday. It's going to be hot; we'll see what happens...

Thanks for the replies!

Pat in Menifee, CA

[dougrainer]

Older Tiffin's including your Year model had the same problem with the 20 amp breakers tripping in extremely hot temps. It was compounded by the fact the Breaker panel was in the REAR Closet right above the engine. You had 2 things causing the trip--extreme heat when camped and the Heat from the engine compartment while in transit So, Tiffin stated that going to a 25 amp breaker would not cause any harm. I have done probably a dozen Tiffin's and replaced the 20 amps with a 25 amp and the problem went away. They also recommended that a return and cold air exhaust vent be installed in the rear back wall closet which we did. The 120 wire is 12 gauge and you will not have any safety issue with replacing with 25 amp breakers. Where is your 120 breaker load center located in your RV? Doug

[Bill_Satellite]

Hopefully, he meant that the same thing happened whether plugged into 50 amp shore power OR running the 10K genny!

[wa8yxm]

I assume you meant you are tripping branch breakers This happens for one of several reasons and .. .they may "Cascade" (that is one leads to another) As I am dealing with it as I type.. More later.

First: All my A/C's (total 4, though only 2 at any one time) if the condenser coils get clogged and air does not flow.. What you got is what I had. Now for most A/C's you go topside as the song says "Up on the roof" and remove the outer shroud. (Coleman go to "Skip)
THen you need to remove an inner cover over the Condenser. this may involve anything from a few screws (Carrier for example) to cutting some metal tape and bending tabs (Advent air.. NOTE you can only bend tabs so often).

Now if you have dainty hands like mine (XXXL) you need to remove the fan. Usually this involves a pair of common pliers and a spring ring. Sometimes screws or bolts.

(SKIP POINT)

Now you can clean the condenser (NOTE you can inspect w/o fan removal)

Also compressed air may blow it clean without fan removal (Except on Coleman)

I do not recommend water (Mell of a hess that way)

Coleman is different because though most A/C's BLOW air through the condenser. Colemans Suck it in

ON my coleman (And my Modified Advent) I remove the outer cover, peal off the cottonwood, and replace the outer cover. (The mod,,, Wheb the made in china fan turned into a china bomb and went BOOM (I do mean BOOM) I replaced with a COLEMAN fan. fits perfectly and SUCKS instead of blows WOW).

Next. A bad motor can crank up the amps

And finally.. I am told by wiser heads than mine a bad Run/Start cap can do it. Replacement on order, Install set for Week from Thursday.

Finally...

As heat builds in the system (OR for that matter outside the RV) the pressures in the system increase. as the pressure builds the compressor draws more and more power tilll........ CLICK it stops.

[ferndaleflyer]

I don't think running the gen while hooked up to shore power matters because only one source is providing power, not both.

[MrWizard]

check and clean your a/c units
inside and outside
replace filters

check the screw connections on the breakers, make sure they are tight

i ran (2) a/c units on a 5000w Onan at 117* a couple of weeks ago

[dubdub07]

John S. wrote:
My old 2001 42 foot Foretravel had three AC units and would run fine at those temps all the time on either shore power or the generator. I never had one blow a breaker. Now getting the coach cool was harder and they ran all the time and I had the fan on high all the time but we got it down into the 70s and kept it there all day when the temps were 100 plus

Lots and lots of mediocre with my Discovery, but the one thing that is OUTSTANDING is the 3x 15,000 A/Cs on the top. In the southeast or the northwest.....Texas or Utah......cold. Freezing cold.

If it is the genny and shore 50 amp, there is an issue with your power commander, I would bet. The load is just too much for some component in the system.

W

[John_S_]

My old 2001 42 foot Foretravel had three AC units and would run fine at those temps all the time on either shore power or the generator. I never had one blow a breaker. Now getting the coach cool was harder and they ran all the time and I had the fan on high all the time but we got it down into the 70s and kept it there all day when the temps were 100 plus

[tropical36]

PCarnathan wrote:
We have a 2009 Mandalay 43A with three rooftop air conditioners. While at the Colorado River a few weeks ago with outside temperatures exceeding 110 degrees, the air conditioners started tripping their individual breakers. I could reset the breakers, but within twenty minutes or so they'd trip again. Eventually, one of the air conditioners stopped working altogether until very late at night.

Each air conditioner is pulling around 14 amps (I checked). Here's the kicker: This happens while plugged into 50-amp service at the campground as well as running on the 10,000-watt Onan diesel generator.

The RV tech is telling me "... it's just too hot." Well, shoot, I guess I shouldn't run the air conditioners when it's hot?!

Do you have any thoughts?

Pat in Menifee, CA

I assume the breaker is hot to the touch, when it trips?
What's the voltage, with all three running?
If you're good, then try leaving your breaker box door open, for getting some air.

[Weldon]

When the one quit working did the other two perform as they should?

[MountainAir05]

If you have not clean the unit in the past few month, its time. Were you on high cool or low cool with the fan. Freezing up to also cause this, but I would check the unit.