Three A/C operation?

[danemayer]

But only 2 of the compressors will ever be running, if I'm understanding this right.
So I don't understand why Heartland puts 3 units on the trailer.

Two A/C units will be on 1 power leg and the third on the other leg. Each leg carries about 6,000 watts from a 50 amp shore power pedestal. Each A/C unit draws less than 1,800 watts. So two A/C units wouldn't need more than 3,600 watts from their respective power leg. All three A/C units should be able to run.

The PCS load management will come into play if you're also running other electrical devices, like the microwave/convection oven, coffee maker, electric side of the water heater, dryer, etc.

When using an on-board Onan 5500 generator, it's more limited because each leg is limited to either 30 amp or 20 amp at the generator. So each leg will provide maximum of 3,600 watts. You may still be able to run two A/C units on one power leg, but it's more likely that the PCS load management will intervene.

Your problem sounds more like it's something wrong with the A/C unit that's not doing much cooling.

 

[TXgearhead]

Two A/C units will be on 1 power leg and the third on the other leg. Each leg carries about 6,000 watts from a 50 amp shore power pedestal. Each A/C unit draws less than 1,800 watts. So two A/C units wouldn't need more than 3,600 watts from their respective power leg. All three A/C units should be able to run.

The PCS load management will come into play if you're also running other electrical devices, like the microwave/convection oven, coffee maker, electric side of the water heater, dryer, etc.

When using an on-board Onan 5500 generator, it's more limited because each leg is limited to either 30 amp or 20 amp at the generator. So each leg will provide maximum of 3,600 watts. You may still be able to run two A/C units on one power leg, but it's more likely that the PCS load management will intervene.

Your problem sounds more like it's something wrong with the A/C unit that's not doing much cooling.

Alright, the Subject Matter Expert has spoken! The center A/C will be checked when I go back to my repair shop to get the defective Carefree slide toppers replaced.
Thank you sir!
I need a drank.

 

[GK2018]

We're currently in the same boat as you but with only two AC's. It was 93 degrees for a high yesterday and we never cooled less than 82 in the RV with both units running constantly. I'm in the process of figuring out what our next step is. I know our former Mallard M33 cooled off way better than this one does. I'm working on devising a plan to add two portable AC units that plug into 120V outlets to help assist these two rooftop units especially seeing how we haven't even hit 110 degree temps yet and we're already sweating inside... I definitely feel your pain!

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[Flick]

But only 2 of the compressors will ever be running, if I'm understanding this right.
So I don't understand why Heartland puts 3 units on the trailer.

Ok. Here’s what we did and what caused me to do what we did.
When we got our Cyclone, we could only use (at one time) the middle and front or the middle and the rear. There was a switch under the main control panel that would let you toggle between the 2 choices.
I installed an extra breaker, separated the ac’s from the switch and this allowed me to run all 3 ac’s at once while on 50 Amp service.
This certainly helped but the middle ac struggled. Everything was checked to no avail. I then decided to replace the middle ac. Upon removing the original, we found that we had a faulty seal between ac and roof. This had allowed water to ease into the roof cavity and was rotting away the wooden trusses. This had damaged a lot of the foil backed tape and was allowing some air to escape into the roof cavity. This damage was not visible from inside the unit.
Fast forward. I repaired the roof and since I already had purchased the replacement ac, installed it. I refoiled and completely resealed so no air could get into the roof cavity.
It performs much better and on a hot day, laser temps from this ac unit are in the low 50’s and that’s all I think I can expect. With all 3 units running, it’s comfortable.

 

[RickL]

As I stated prior, with my Landmark Oshkosh I can run all 3 A/C’s at the same time with no special things to do. Just set the thermostats and wait for the trailer to cool off. As we spend a lot of time in hot areas, usually 3 months in Moab July-September and then Yuma where temps are in the 100’s we have no problem maintaining 70-72 degrees.

 

[TXgearhead]

Just pulled into RV park (Catherine's Landing) in Hot Springs Arkansas. Call it 5pm. Turned on all 3 A/C's. Thermostat shows inside temp at 90. Progressive EMS showing 28 amps on line1, and 28 amps on line 2.
Report forthcoming.

 

[TXgearhead]

Two hours later, 7pm, we're down to 86F, about ambient. Waiting on sunset.

 

[avvidclif]

Just remember it not only has to cool off the air but also the walls, ceiling, and furniture. Everything in there is hot.

 

[TXgearhead]

Oh yeah. 10-4.
It got down to the high 70's about 8pm, comfortable.

 

[TrailCreek]

Has anyone tried runnibg one AC while driving? I'm hoping that a small generator could run it from the truck bed.

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[TXgearhead]

Define small.
I'm thinking you'll need 3,000 watts unless you have a soft start capacitor.
Sounds like a PITA.

 

[TrailCreek]

Thats the plan, added soft starts to all three AC's. Hope to take the factory generator connection and run a cord to a Honda EU2000 in the truck bed. Just to run one generator.

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[TrailCreek]

One AC I meant.

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[TXgearhead]

Maybe a solution to my cooling issue. When we got home from Iowa I scheduled a visit to my Mom & Pop repair shop. I got their diagnosis this morning. The middle A/C compressor wasn't pulling enough amps. Shop wants to replace the entire unit. Goes against my Good Sam $500 per visit deductible. They will also check my gray water valve not working.

 

[TXgearhead]

That fixed it. New middle unit A/C. You can hang meat in there now.

 

[Flick]

That fixed it. New middle unit A/C. You can hang meat in there now.

Like the post said that I had sent you, the new ac along with some roof repair fixed our problem also. Sometimes you just need to bite the bullet. Glad your repair guy was spot on.

 

[TXgearhead]

^^Yeah, they're good people. Just parts and repairs. Channelview Supply Co. Family owned and operated. East side of Houston, the working side of town. Been doing business with them about 40 years.