RV A/C in Arizona summer heat?

I’m in phoenix as we speak and the temps are finally in the 70s. I have two a/c units and the one over the main living space ran nearly all day yesterday and it was losing ground. It’s not so much the ambient air temp as it is the intensity of the sun beating down on the MH. It’s quite impressive.

We spent this past summer in N Mex at 4,200 ft with many days 100+ but high only to 108. The A/C ran day and night, sometimes shutting off for a period of time during the night. Make sure you pull shades, curtains including over the door to block any sun you can from coming inside. The silver windshield type things in the windows will work better. Try to park with some shade. The sun in 1 summer bubbled the clearcoat on the front bumper of our rv. It is hot, hot, hot! It will get way to hot inside to leave your pets without the A/C set to run.

When we camp in hot temps the bedroom AC sounds like an aircraft engine while trying to fall a sleep. We use the bedroom fan right up until we crawl in bed and then switch to a free standing oscillating fan to move air while we sleep.

2oldman wrote:

Old-Biscuit wrote:
That would be tough to do......A/C capability IS at best 20*F differential measured at Return (inlet to Evap Coil) and Discharge (outlet side of Evap Coil)

Put your hand on any a/c and feel it. It's pretty cold. If your trailer was 90° and your air was blowing 70° at best it would take forever to cool down.

I've measured my air temps, so I know I have a magic a/c.

Recalling my university studies, it was not recommended to have a high differential between ambient temperature and the A/C discharge temp as it creates drafts and complaints from room occupants, that recommendation was proven correct in my dealings with people in offices etc.

Not sure if the RV A/C manufacturers followed the rule, but I suspect they did. Quantity of air flow is the more critical component to good cooling at a reasonable temp differential.

One thing that you need to do is maintain the fan at full speed and regulate the thermostat, we learnt that one night when wife asked if we could reduce the fan noise, I turned the fan speed down and went to bed.

Arround 03:30 the A/C shut down, outside temp was 92, I took the filter cover off on the Dometic and discovered that the evaporator was frozen, fast thinking used wifes hair dryer since it was a very thin accumulation of ice on the fins to melt the ice, checked brakers and all was O.K. turned A/C back on and from then on regulated temperature only and maintained the fan on full speed, talking to other guests they confirmed the fact that A/C units do freeze up when the monsoon hits in Arizona.

Depending on the temperature you might have to run the A/C at night also, another thing that we have done is use the cloth that the greenhouse growers use, sold at Home Despot at the gardening shop to cover the rear window, the ladder sits there and helps as a tie down, also try to shield the refrigerator from direct sun, and if posible install a small computer type fan, we have one that runs on 110 Vac, one runs on 12 V dc and one that is solar powered, place the fan at the top it is better that down near the heater, I turn the fans on depending on what we need and where we are, this keeps the refigerator at a beter temperature than the house unit.

navegator

2oldman wrote:

Old-Biscuit wrote:
That would be tough to do......A/C capability IS at best 20*F differential measured at Return (inlet to Evap Coil) and Discharge (outlet side of Evap Coil)

Put your hand on any a/c and feel it. It's pretty cold. If your trailer was 90° and your air was blowing 70° at best it would take forever to cool down.

I've measured my air temps, so I know I have a magic a/c.

:S

Old-Biscuit wrote:
That would be tough to do......A/C capability IS at best 20*F differential measured at Return (inlet to Evap Coil) and Discharge (outlet side of Evap Coil)

Put your hand on any a/c and feel it. It's pretty cold. If your trailer was 90° and your air was blowing 70° at best it would take forever to cool down.

I've measured my air temps, so I know I have a magic a/c.

2oldman wrote:

Old-Biscuit wrote:
18*F-20*F differential between RETURN air and DISCHARGE air temps is what the A/C Unit should be capable of achieving

Mine does much better than that.

That would be tough to do......A/C capability IS at best 20*F differential measured at Return (inlet to Evap Coil) and Discharge (outlet side of Evap Coil)

Only for a couple weeks?
What time of summer?
It's not always 110* in AZ.

Thanks all folks. Good tips. Think us and the critters will be ok. Totally understand about keeping it cool rather than try to play catch up. Not worried about the electricity bill for a few weeks. We'll get closed and moved in and then head back north until fall.