Need AC help STAT! Melting in AZ

[AZamberose]

Just bought a new 2023 GD 3740bh to live in full time with my son. Temps here in AZ have been 113-116 all week. I had both Coleman AC units set to “Lo Cool Auto”, I set the main thermostat to 83, and the bedroom thermostat to 78. I also installed a portable unit in the master that is set to 76 overnight and 80 during the day. I was advised to close the master bedroom dump vents and set that thermostat lower, since the portable AC is near it and it was not kicking on to help the main AC. I was also running a floor fan in the second bedroom to help circulate the air. When it is 113 outside it was staying around 88 inside the camper. After more than a month of running the two AC units, the fan, and the portable, I have recently come home to BOTH AC units shut off on their own (thermostat shows “off”). Not sure exactly when they turned off, but they came right back on when I reset the thermostat, and continued to run without issue until the second time (a few days later) I came home from running errands and they were “off” again. I checked the filters and they were clean. I make sure to reduce all other power suckers, as I know the units are working hard in this weather. We have put up shade screens on both sides of the camper, I installed heat blocking window film, and we are soon installing skylight and vent shade covers. My question is, why would the units shut off on their own? Is there a better way to set everything so it is cooler in the unit? Thanks in advance for your help!

 

[Hoopy Frood]

Do you have an EMS? Just a thought, but you could set the thermostat to Lo Cool, not Auto. This will keep the fan running, but the compressor will start and stop as determined by the thermostat temperature setting. Probably won't do much but it might lower the load when the compressor starts, as the fan is already running.

And unless you have to be there, it might be advisable to leave the area til the high heat abates a mite.

 

[ajg617]

Almost sounds like an AC power loss for both of them to do that assuming you are connected to shore power.

 

[Second Chance]

Almost sounds like an AC power loss for both of them to do that assuming you are connected to shore power.

The thermostats are DC, so when shore power comes back on, the ACs should start back up on their own (if everything is controlled by a One Control system, I don't know anything about that).

My advice for [MENTION=61517]AZamberose[/MENTION] is to set the thermostats on Hi/Auto. Low fan can allow things to freeze up - though not as likely in AZ with low humidity.

Rob

 

[trailrydr]

[MENTION=61517]AZamberose[/MENTION],

We dont get usually get the 110+ degree days here in the midwest... but have had some 105 degree days. What we did to increase our AC cooling effiency:

A) place soft starts on both AC units. Reduced the initial amp pull by 50%.
inspect and clean reusable filter (purchased extra sets for quick replacement), evaporator and condenser coils.
C) purchased/placed 98% blackout thermal curtains on every window.
D) purchased/installed slide toppers over each slide.
E) purchased/installed MaxxAir vent hoods over kitchen and bath vents.
F) purchased/installed slim shade door window replacement.
G) purchased/installed bathroom skylight thermal pillow insert.
H) installed a kitchen ceiling fan to circulate air.
I) installed my own version of the RV Airflow System (both ACs) to force all AC air into ceiling race track system. Purpose was to have cool air fall in multiple locations instead of dumped out of the AC units.
J) replaced both OEM MaxxAir thermostats with MicroAirs. Easier to control using App.
K) had RV Armor installed on roof.

By doing the maint and upgrades, we have been able to keep our thin walled/single pane windowed '19 295RL at 73F on days at 105F for the last 2 years and cycling on/off while doing it.

 

[Riverbug]

I concur with Rob. We've always been told to put the A/C on high auto as using low settings can create freeze up conditions. Also, when it's that hot what would be the benefit of running on low anyway? Wouldn't you want to high output for better cooling?

Regarding the powering down issue, is it possible the power supply is fluctuating or blipping at the park you are in? With it so hot, perhaps the grid is having trouble keeping up? Years ago I recall something about the inconsistent power in a park we stayed at was causing a/c units to shut down without tripping breakers or anything else. But I do not recall the details about it and at the time our RV was several years old and it didn't seem to have the same sensitivity as the newer ones, so we didn't have the issue that others were having. That was also a very hot summer and the park had a pretty old electrical system.

 

[ajg617]

The thermostats are DC, so when shore power comes back on, the ACs should start back up on their own (if everything is controlled by a One Control system, I don't know anything about that).

My advice for [MENTION=61517]AZamberose[/MENTION] is to set the thermostats on Hi/Auto. Low fan can allow things to freeze up - though not as likely in AZ with low humidity.

Rob

Unless the battery(ies) ran down during the time away (maybe not so hard in that heat) - with the OP saying he turns off all other power suckers, I'm curious why and what - should be steady state and a 50amp connection should run everything. If I remove DC power, it will set the thermostat's back to 'off' once I connect again.

As you mention, we always run ours on Hi/Auto (both Colemans with AirXcel thermostats).

We hit 106 in South Dakota and 112 in Wyoming in our first year and internal temps were in the mid-70s after running for awhile post travel - and they stayed there. We were also told to keep the dumps closed if we had RV Airflow (our main AC came with that installed from the factory) or we could ice up. Maybe the dual panes really helped but I had Soft Starts installed after the first season. Other than that, we are all stock with a two-AC unit. But in general, we've found that the bedroom AC (15K BTU) puts out far more cold air than the bedroom needs so I usually lower the T-stat there a couple of degrees during the day to help out the larger living area.

 

[Tony_in_AZ]

We lived in the AZ heat in 2021 with a different brand RV toy Hauler about 40 ft long. Both ACs were on Hi Auto Kool.. We also had a floor AC 120v unit. Our AC never shut off by themselves. They were Coleman 15k AC units

Best temp we could see during the day was 90 inside the RV. It was miserable. I bought 1 inch thick hard foam insulation and stuck that on several interior walls. Covered windows with the silver bubble insulation.

 

[traveldawg]

Just bought a new 2023 GD 3740bh to live in full time with my son. Temps here in AZ have been 113-116 all week. I had both Coleman AC units set to “Lo Cool Auto”, I set the main thermostat to 83, and the bedroom thermostat to 78. I also installed a portable unit in the master that is set to 76 overnight and 80 during the day. I was advised to close the master bedroom dump vents and set that thermostat lower, since the portable AC is near it and it was not kicking on to help the main AC. I was also running a floor fan in the second bedroom to help circulate the air. When it is 113 outside it was staying around 88 inside the camper. After more than a month of running the two AC units, the fan, and the portable, I have recently come home to BOTH AC units shut off on their own (thermostat shows “off”). Not sure exactly when they turned off, but they came right back on when I reset the thermostat, and continued to run without issue until the second time (a few days later) I came home from running errands and they were “off” again. I checked the filters and they were clean. I make sure to reduce all other power suckers, as I know the units are working hard in this weather. We have put up shade screens on both sides of the camper, I installed heat blocking window film, and we are soon installing skylight and vent shade covers. My question is, why would the units shut off on their own? Is there a better way to set everything so it is cooler in the unit? Thanks in advance for your help!

I'd guess power interruption and thermostats that don't come back on. Check your 12v circuit to be sure the DC disconnect is in the proper setting.

Run all Acs on Cool Hi - all the time; close the dumps and use the roof ducts. Set both at the same temperature and leave them there. Fans help. A portable AC would help too but placement would be critical. Keep you window shades down.

Most likely with temps over 100 degrees outside you will never get a cool RV.

Things that help - having an EMS that reports power outages; double pane windows; awnings/covers over large windows; slide toppers.

I'll assume you are there because you have to be (for work, family, whatever).

 

[RV2600RB]

You should have no problem keeping the rv cool in that temperature with dual a/c.
Our 35ft fifth wheel with dual air conditioners could stay at 70* all day in heat like that (southern AZ). We always ran the a/c on auto.
Maybe the park had power surges due to high power consumption in the heat. I’ve run into low power during high heat on 30amp service.
I’ve used a voltage regulator before with good results.
Sorry, I can’t help with Coleman, I’ve only had Dometic. And now Furrion
Rich

 

[lineman1234]

What happened to the OP???????

Its always nice when a person posts back with the final information.

 

[Riverbug]

What happened to the OP???????

Its always nice when a person posts back with the final information.

I wondered the same thing. I think they packed up and headed north.

 

[TrueHeeOHs]

OP, agree with everyone else to set to Hi fan speed.

I have to ask, the portable unit you mentioned, does it have vents for BOTH intake and exhaust on the hot side? If not, throw it out. If it does, ensure they are Intaking/exhausting out a window. Otherwise you’re hosing yourself.

 

[gkchristopher]

A Delta T of 25 degrees is actually doing well. It's just too darn hot there. I'd would also recommend keep the fan on high to get as much airflow across the evaporator as possible. Check all your vents to make sure none are blocked or closed.

 

[wmgoat]

another thought

I concur with Rob. We've always been told to put the A/C on high auto as using low settings can create freeze up conditions. Also, when it's that hot what would be the benefit of running on low anyway? Wouldn't you want to high output for better cooling?

Regarding the powering down issue, is it possible the power supply is fluctuating or blipping at the park you are in? With it so hot, perhaps the grid is having trouble keeping up? Years ago I recall something about the inconsistent power in a park we stayed at was causing a/c units to shut down without tripping breakers or anything else. But I do not recall the details about it and at the time our RV was several years old and it didn't seem to have the same sensitivity as the newer ones, so we didn't have the issue that others were having. That was also a very hot summer and the park had a pretty old electrical system.

Could also be your surge protector, if you are using one.

 

[lineman1234]

Before buying a portable AC unit, for my last TT, i did extensive research on them. The way to pick one is going by the ( sacc ) ratting, ( not ) the BTU ratting.

Dual hose...................... Puts the hot air outside, sucks in hot air from outside, may have a dump tank or may put the humidity taken out of the air in the exhaust. So has to cool the hot air from outside for inside.

Single hose................... Puts the hot air outside, also may have a dump tank or put the humid air outside. Takes the inside air, just like an RV roof mount AC unit and cools it. So it works less to cool the inside are vs the hot outside air used by the dual hose.
That said, creates a vacuum or still gets some air from outside to compensate from the exhausted air. No need to crack a window as i havent come across an RV that is air tight.

Going by the sacc ratting and what i could get local, i went with a single hose unit, and was very happy and impressed with it.

 

[RV2600RB]

If the air conditioning is functioning properly, there is no need for a portable one. The factory a/c should easily keep your rv at 70-75* in 100*+ temps. It should also function properly on auto. No need to keep it on high all the time.
We travel mainly in the desert southwest and during hot summer months. Never had an issue until we ended up with the furrion system in this one. Still working on making it useful. Grrrr
Wish I had the money to replace it with a Dometic. Never had a problem with those.
Rich

 

[gfl123]

Before buying a portable AC unit, for my last TT, i did extensive research on them. The way to pick one is going by the ( sacc ) ratting, ( not ) the BTU ratting.

Dual hose...................... Puts the hot air outside, sucks in hot air from outside, may have a dump tank or may put the humidity taken out of the air in the exhaust. So has to cool the hot air from outside for inside.

Single hose................... Puts the hot air outside, also may have a dump tank or put the humid air outside. Takes the inside air, just like an RV roof mount AC unit and cools it. So it works less to cool the inside are vs the hot outside air used by the dual hose.
That said, creates a vacuum or still gets some air from outside to compensate from the exhausted air. No need to crack a window as i havent come across an RV that is air tight.

Going by the sacc ratting and what i could get local, i went with a single hose unit, and was very happy and impressed with it.

I did this , and used some duct insulation around the single hose, as it seemed to get pretty hot itself. this in a single a/c 33' fifth wheel.

 

[lineman1234]

Your right, i forgot about that. I did put reflexit insulation on the hose, it did get hot.