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Old 07-01-2019, 09:35 PM   #1
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Poor AC on new (2019) GW 23DBH

Picked up RV two weeks ago and went off to the south...hot weather for sure but was very disappointed to have 90F and 82F inside.

Our last trailer was only two years old (21ft) and had the Dometic Brisk2 replaced under warranty under due to know poor quality...new trailer may have issue too.

Anyone else care to comment on their 23DBH if a single 13500 BTU can do the job...or not.

I walked to people with 27-30ft with single AC (maybe 15K BTU?) and said they were keeping cool...but didn't know specific temp.

I keep a ambient inside/outside digital thermometer with humidity so I know what to expect.

TO small AC for a 23DBH or most likely low pressure due to the poor (known) quality Dom Brisk@?
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Old 07-02-2019, 02:53 AM   #2
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I have an 18MT with the same AC unit as yours. Your trailer is about 5 ft longer than mine according to specs, so this may or may not apply to you, but I thought I'd share.

When I got mine a month ago, it too failed to cool well. I noticed that when I turned it on, the air exiting the unit would be nice and cool, but then after a short period of time, the air exiting the unit seemed to warm up. It's a little difficult for me to hear the compressor cycle on this unit, but using an infrared thermometer I then purchased, I was able to determine that the compressor was shutting off prematurely. Even when I had the thermostat on the air box set to max cold.

A quick search turned up this blog post.

I followed what he did, but I noticed the adjustment screw on mine was different. It's a very small phillips head screw. I adjusted it about 1/2 of a turn clockwise to start. I had to wait for our next trip to test the AC, as I don't have anywhere to plug the TT in at home that can supply the required current to run the AC.

Camping this past weekend, it was in the 90's and close to 100% humidity. I fired up the AC, set the thermostat control to max cold, and left the campground for lunch. When I returned, my windows had condensation on the outside, and the interior of the trailer was about 50. That turned out to be too much adjustment, as the unit would freeze up.

I backed off the screw about 1/4 turn, so now I'm only about 1/4 turn clockwise from its original position. Now the unit cools to around 63 in the same outdoor conditions, and doesn't freeze up.

Messing with it would probably void my warranty, but I didn't feel like waiting for the dealership or Dometic to figure it out, and it was a simple enough process to reverse if need be. Whether or not you feel the same is, of course, up to you.
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Old 07-02-2019, 11:47 AM   #3
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Looks like that unit has a ducted A/C. There are several threads here about the partition between the supply and return plenum not being sealed, also about ducts not being hooked up, crushed, and leaking. I'd start by checking all those things that I could and see how much of it you can fix. You may be surprised how well you can get it cooling your RV.
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Old 07-02-2019, 01:11 PM   #4
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I didn't see that it had ducted AC. The thermostat adjustment I did probably does not apply to yours then.
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Old 07-02-2019, 01:15 PM   #5
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Hi guys it is ducted and the flow from the ducts does seem good.

The temp at the exits is approx. 58-60F irregardless of outside ambient but I note my car and boat (different types of ac I understand) often can show 45-55F at the duct.

I'm very curious if anyone is running at 13.5K in a 22-25ft trailer and getting 15-20 temperature difference between outside and internal. I know these things are not efficient and thermal load from the sun can pay it due but it seems like there is a lot of mixed data out there on who gets these things cool vs. those who say they are never happy.

I'm several weeks ago from getting this back to the dealer with my list of 101 issues.
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Old 07-02-2019, 02:42 PM   #6
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You'll want to measure the temperature differential vs the intake air, which would be the inlet on the AC unit in your trailer, on the ceiling. They don't suck in outside air.

Hopefully someone with that model will chime in with an answer as to whether the 13.5K can keep up.
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Old 07-02-2019, 02:45 PM   #7
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You'll want to measure the temperature differential vs the intake air, which would be the inlet on the AC unit in your trailer, on the ceiling. They don't suck in outside air.

Hopefully someone with that model will chime in with an answer as to whether the 13.5K can keep up.
So if the ambient inside the trailer is 80F and the outlets are producing 60F (lets' assume about 50-60% humidity) is that within spec?

When does outside temp come into play? Seemed pretty crazy that it was 90F outside (varying humidity didn't seem to impact inside temp) and at best seeing 82F inside.

Others chime in please!
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Old 07-02-2019, 03:28 PM   #8
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Here's how that delta-T works.

When you start out the temp in the RV is say 90F and you turn the A/C on. Give it a few minutes the inlet side temp will be 90F and the air coming from the outlet side should be 70F (using round numbers). As the A/C runs for a while the RV cools down so now the temp of the inlet air is 80F then the corresponding outlet air temp should be 60F. As the inside temp gets further and farther below the outside ambient temp, more and more heat load is transferred into the RV so it takes the A/C longer and longer to cool the inside air anymore. To a point where the gained heat equals the cooling capacity of the unit and no more cooling will occur.

So it's not that on a 90F day the A/C will only ever output 75F air. If the A/C condenser were sitting outside in the heat that would be the case, but in even a slightly insulated enclosure it should gain some cooling below that.
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Old 07-03-2019, 03:19 PM   #9
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Here's how that delta-T works.

When you start out the temp in the RV is say 90F and you turn the A/C on. Give it a few minutes the inlet side temp will be 90F and the air coming from the outlet side should be 70F (using round numbers). As the A/C runs for a while the RV cools down so now the temp of the inlet air is 80F then the corresponding outlet air temp should be 60F. As the inside temp gets further and farther below the outside ambient temp, more and more heat load is transferred into the RV so it takes the A/C longer and longer to cool the inside air anymore. To a point where the gained heat equals the cooling capacity of the unit and no more cooling will occur.

So it's not that on a 90F day the A/C will only ever output 75F air. If the A/C condenser were sitting outside in the heat that would be the case, but in even a slightly insulated enclosure it should gain some cooling below that.
Correct! And I might stress that the time needed to cool down a hot RV can be considerable. Plus where you set the thermostat, as long as it is below ambient indoor temp makes no difference. The A/C will run at full capacity 'till the thermostat is satisfied. Thus, I wouldn't ever turn the thermostat to "off" when using the RV, just set it where you want it, and leave it alone.
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Old 07-03-2019, 06:58 PM   #10
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Correct! And I might stress that the time needed to cool down a hot RV can be considerable. Plus where you set the thermostat, as long as it is below ambient indoor temp makes no difference. The A/C will run at full capacity 'till the thermostat is satisfied. Thus, I wouldn't ever turn the thermostat to "off" when using the RV, just set it where you want it, and leave it alone.
The RV AC was running all night/today for observation nation. Got to 85F today with high humidity (didn't get reading). I noted the air vents (4) and the bottom panel of the AC were covered in water...more then I ever saw while visiting Florida...it was dripping off regularly onto the floor but then drying on the floor.

Is this to be expected in 85F temps with high humidity...or is this a sign of poor cooling and/or efficiencies.
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Old 07-03-2019, 08:48 PM   #11
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Your temp range of 90 out and 82 inside is the appropriate range for AC.
An 8 degree drop isn't bad.
Check all filters, confirm strong airflow being discharged.
Check the temp at the return intake duct and compare with the temp discharge... it should be about 8 degrees cooler coming out. Let it run another 30 minutes and check again.
As it gets cooler in the room the intake will be cooler and output will get cooler.

Keep in mind humidity affects cooling rate.
A 13.5K and even 15K RV AC unit can only do so much depending on insulation and temps outside.
A ducted RV AC unit moves more air and cools better than a single ceiling control and outlet.

Direct sun keeps those temps in your RV 'box' up and AC struggling.
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Old 07-03-2019, 09:33 PM   #12
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To the OP, are you in full sun or shade? Are there any vents or windows open? How often is the door opened? Is your awning out? My trailer is 30' with one large slide. Most trailers are not insulated well and the slides are probably worse. Shade makes a huge difference on my trailer. 90 in the sun and my trailer may ne 85 inside. 90 in the shade and it will stay close to what I sat it at. The condensation that you have makes me concerned that either you have some outside air coming in (from vents, windows, or open doors) or that the divider in the return/discharge area is not sealed off. I was in Charleston two weeks ago and it was high humidity in the 90s with some late day shade. No shade in the morning or at noon. Too keep the trailer cool I had to threaten the kids so the door would stay shut. I get up early every day so when I would wake up I turned the thermostat down to 65. That way we would start out ahead of the heat.
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Old 07-03-2019, 09:34 PM   #13
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The water forming on the cold air surfaces is condensation, an indicates very high humidity. You should also see a stream of water running down the outside, unless the drain hole(s)is/are blocked.
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Old 07-03-2019, 10:00 PM   #14
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Looks like that unit has a ducted A/C. There are several threads here about the partition between the supply and return plenum not being sealed. I'd start by checking all those things that I could and see how much of it you can fix. You may be surprised how well you can get it cooling your RV.
^^^^^^^^^^ What he said.^^^^^^^ 99.9% of the partitions are not sealed. When we sealed ours make a huge difference.


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Old 07-04-2019, 07:51 AM   #15
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Good info guys...lots to consider, but...

1. I never had these issues with our 21ft unit the crappy Brisk2 died in the 2nd summer.
2. These trailers seem painfully under ACd. I come from the world of larger boats and have no issues like this. We has a 15k BTU in a 37ft Sea Ray and could keep that think in the mid 60s on 94F days...with the door open!!

Ill check for leaks but for those asking about sun/shade...its camping. It changes. In Florida it was in mostly sun while at home its half shaded and still struggles. It was 80F yesterday and 72F was all it could hold with nobody going inside and out.

For those saying what is the ducted air flow...how am I to know? Air comes out of 4 vents but I have no way of telling what is acceptable.

Very frustrating. Hopefully something is wrong with the unit. I know perception drives our reality but to me...I cannot believe many of you put up with this!! Yes we are spoiled.
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Old 07-04-2019, 09:59 AM   #16
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All my research on ducted TT/RV AC (and even my non-ducted unit exhibits this) points to the same thing. And that seems to be the poor seal between the intake and the output duct plenum in the unit's airbox. I'm new here, and not 100% sure what the policy on linking to other forums is, so I won't, but a quick Google search will pull up this issue all over the place, and in many different manufacturers. I plan to get some aluminum tape and seal mine up.

It is annoying that we have to deal with these things. It would be great if they came from the factory without these annoying flaws. They don't though, so whatever you don't catch in a PDI, you can either deal with yourself, or rely on the dealer's service to make it right.

Personally, I bought my TT to camp, not to have it sit at the dealership. So I fix what I can by myself.
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Old 07-04-2019, 10:19 AM   #17
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During the day with sun on the roof I run the fan on high and dump straight down from the a/c unit instead of using the ducts. If I run through the ducts the heat generated from the roof heats the ducts and kills the cooling ability. Your ducts will be heated and your a/c will struggle. I can effectively lower my inside temps 10 degrees by not using the ducts and dumping the air directly from the a/c. This is on a 26dbh so a little bit longer too. BTW don't run the unit on auto in high heat. It will switch back and forth between high and low and when it gets behind it is a losing battle.
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Old 07-06-2019, 09:59 PM   #18
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We have a new Cherokee 274vfk that is a 34' travel trailer with a single 15k BTU ducted AC unit. Earlier this week I had it in Alabama with temperatures in the mid 90s and high humidity. I had the thermostat set for 70 degrees. When I first hooked it up, it took about an hour to bring the temperature down to the thermostat setting. After that, the unit cycled on and off and kept the trailer at 70 degrees regardless of the outside temperatures. It was on a mostly unshaded space.

I had read the above posts and had some real concerns as we're still getting to know our new travel trailer. Thankfully, it seems that it's well-insulated and pretty tight because the AC had no problem keeping the trailer cool. When we first got it, we kept it warm with outside temperatures in the 30s by using two electric heaters on the low 750 watt settings.

Bill J., Lexington, KY
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Old 07-08-2019, 09:18 AM   #19
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Tint your windows with ceramic tint and use reflux in the skylights. We plan to do this over the winter. Plus we used a towel fan in the doorway by the master bed door and slide and that helped alot. The problem we very been having it the AC shuts off even on low setting then turns back on after about 1 minute and sometimes never turns on unless we shut the thermostat off wait a 1 minute then turn it back on.
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Old 07-08-2019, 10:33 AM   #20
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We have a new Cherokee 274vfk that is a 34' travel trailer with a single 15k BTU ducted AC unit. Earlier this week I had it in Alabama with temperatures in the mid 90s and high humidity. I had the thermostat set for 70 degrees. When I first hooked it up, it took about an hour to bring the temperature down to the thermostat setting. After that, the unit cycled on and off and kept the trailer at 70 degrees regardless of the outside temperatures. It was on a mostly unshaded space.

I had read the above posts and had some real concerns as we're still getting to know our new travel trailer. Thankfully, it seems that it's well-insulated and pretty tight because the AC had no problem keeping the trailer cool. When we first got it, we kept it warm with outside temperatures in the 30s by using two electric heaters on the low 750 watt settings.

Bill J., Lexington, KY
This sounds pretty amazing. My initial thought was to upgrade to the 15K unit when we go in for fixes...but then I started thinking the extra 1500BTUs may not make a difference if our trailer cannot keep a 7-8F difference as is. You give me hope that our current one may be poor quality plus and upgrade to push hard.
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