ACs wont cool below about 82 to 88 depending on outside temp

[cghsatx]

I have a 2019 3731 with a Dometic 15K heat pump in the rear and and 15K Dometic in the front. I've had problems with cooling since day one (not cool, cutting off, short cycle, all the usual things) I replaced the Dometic thermostats with MicroAir which seemed to help some but I cant believe everyone else sweats in their RVs every summer afternoon. The return air temp with infared sensor varies from 82 degrees in the front/hitch end (west sun) to 75 in the rear. Air from the vents is 48 to 55. Indoor air temp is 82 to 88 depending on time of day. Outside air temp is 105 per the heat pump thermostat. I have the shades down, run the ceiling fan, no cooking or in and out the doors, and have had the windows tinted. I really like the RV except for being miserable in it most of the summer.

The dealer and a 3rd party vender say that is the best it can do but I cant believe everyone puts up with the indoor heat. If I cant find some repairable issue, I guess the next step is to get rid of it for something smaller that can be cooled easier, or paid the bucks for a 3rd AC. The rear AC also has a slight vibration that I dont like feeling through out the RV but again, its "normal" per the dealer. Out of warranty now.

[jsb5717]

There have been a few threads on this issue very recently...probably because it's summer and hot. I would do some searching on this and the Keystone Forum for AC issues. There are some things you should look at to see if your air flow could be better.

Do you have the Whisper Quiet system? That's the one with 2 return vents off to the side of the AC but no plenum on the interior.

This thread might be helpful:

https://www.keystoneforums.com/forum...hlight=whisper

[AZ Traveler]

A 20-25 deg split between outside and inside indicates your a/c is working fairly well. Letting the rig really cool down at night will help. You can add a portable a/c set up inside the rig and vented through a window or add another a/c on the roof if you can't find a cooler place to camp.

Here is an example: https://www.amazon.com/LG-LP1419IVSM...54748520&psc=1 I have no first hand experience with this unit.

[mlh]

I doubt very seriously these AC units put out the BTUs they are rated for. I have a sun room with 5 sliding glass doors 3 sky lights. This glass has R3 value with the sun shining in on a dark floor. My 12000 BTU mini split cooled my 400 foot sun room with a 12 foot ceiling today when it was 97 degrees outside to 72 degrees and only ran about half the time and them not nearly at full capacity.
Lynwood

Sorry I had a misprint. My sunroom is 200 SF instead of 400 SF. I waited too long to correct it.
Lynwood

[DQDick]

We sit directly in the sun in Kansas with temps in the 100's and 70% humidity. We have put pvc pipe in our return air to keep it open, added insulation even in the cabinets, closed off the return air vents to the furnace (under the stairs) and added insulation to the basement as well as a few other minor things. We have no problem maintaining 78 degrees (I'm too cheap to try for less and run on one AC until around 1PM) so there is something wrong with your rig. Besides the things I mentioned I'd also check the ducts directly under the units. Some have found there's weren't sealed properly and were pulling hot air from the space between the ceiling and the roof.

[Mikendebbie]

Greg - I bought a 2011 Jayco travel trailer (i think it was in 2012) from Crestview RV in SA. During the PDI - the tech told me the best thing to do with these ACs in summer in TX is turn it on high and never turn it off. I have taken that advice to heart ever since.

The ACs in our unit will not cool like our S&B on a hot summer day at Port Aransas. We have a Dyson vertical fan that we use to blow on us while we watch TV in the theater seats. It rotates back and forth and covers both dogs on the couch and us in the seats. Moving air and a cold adult beverage makes it tolerable. I recently added two micro air thermostats. We have not been to Port A since the thermostat change, but we always travel with the Dyson fan (because it does not take up much room). Leaving the ACs on high overnight we wake up to inside temps in the 60s…feels goooooood! We like the noise of the AC. We have a small fan blowing across us at night also.

I guess we have accepted the fact that these things are not going to make ice inside the RV during a hot Texas summer day. But we definitely enjoy freezing our buns off and sleeping good at night. Set on high cool and enjoy!

[bcrvman]

Originally Posted by cghsatx

I have a 2019 3731 with a Dometic 15K heat pump in the rear and and 15K Dometic in the front. I've had problems with cooling since day one (not cool, cutting off, short cycle, all the usual things) I replaced the Dometic thermostats with MicroAir which seemed to help some but I cant believe everyone else sweats in their RVs every summer afternoon. The return air temp with infared sensor varies from 82 degrees in the front/hitch end (west sun) to 75 in the rear. Air from the vents is 48 to 55. Indoor air temp is 82 to 88 depending on time of day. Outside air temp is 105 per the heat pump thermostat. I have the shades down, run the ceiling fan, no cooking or in and out the doors, and have had the windows tinted. I really like the RV except for being miserable in it most of the summer.

The dealer and a 3rd party vender say that is the best it can do but I cant believe everyone puts up with the indoor heat. If I cant find some repairable issue, I guess the next step is to get rid of it for something smaller that can be cooled easier, or paid the bucks for a 3rd AC. The rear AC also has a slight vibration that I dont like feeling through out the RV but again, its "normal" per the dealer. Out of warranty now.

I have difficulty understanding what is happening. We are lucky in that the hottest we have seen is about 104 but most days lately closer to 90. I am a heat hater so have thermostats set to 75 (80 is considered responsible). Rig is as mentioned in sig, but to repeat 42' Montana with 1 15k and 1 13.5k.
The units don't run continuously but frequently for sure.
Have you blocked the cold air returns to the furnace?

[DavidG425]

www.ezsnapdirect.com RV window screen goes on the outside, and www shaderv.com to keep the sun off the roof (the sun heats up the "ducts" in the styrofoam insulation under the roof).

Until it gets to over 100 outside, the 3 AC's can keep our coach at 75 or less. We had 113 outside one day and inside only got to78-79.

[Daryles]

Put reflective window film on the outside of your windows.
Here's the results of a test I did using window film

https://www.montanaowners.com/forums...57#post1224357