AC doesn't keep up with heat

[BobsYourUncle]

Not sure if I have an issue or not, but my AC can't get ahead of the heat.

We arrived in Fairmont Hot Springs RV Resort in BC this morning, set up and turned on the AC. It has been running non stop all day, and although it is reasonable in here, it is by no means really cool.

32' TT in sig, with a 12' X 3' slide. It is blowing cool, but not really cold. Unit is a Dometic 13.5.

Temperature outside is 34.3 C, or just under 94F.
Temperature inside is 24.8C or 76.6F. Not bad but I'd like it cooler.

I put my hand to a ceiling outlet and it's cool, but not that cold like I'd expect of AC.

We are pretty much open to the sun, obscured as it is by smoke from half the country being on fire.

Does this sound normal?

[BobsYourUncle]

After all that, the weather turned south.
Second day in the AC was on twice for a while. 3rd day it rained big time.
It has been cool ever since, and a lot of dull overcast days with more rain.
Now the appliance of choice is the furnace.....

Pleaee remind me its the middle of August...

[udidwht]

Remove the AC roof cover. Then remove the cover that shields the condenser. Use some cleaner (no rinse to clean the condenser coil.

https://www.amazon.com/Cleaner-Ounce-Aerosol-Clear-Yellow/dp/B099J9YRMY

[MFL]

While I do not have a cooling issue with my 15K Dometic, I am wondering how to remove the ceiling duct vent covers, to check for leak areas. Mine are plastic, rotating vents, with no visible screws. Do these vents come down by just pulling, or does the base require a twist, other??

Jerry

[down_home]

pianotuna wrote:
Bob,

I suspect the duct work may be "leaking" cold air into the roof (assuming it is a ducted unit).

If you have a generator--perhaps run it for the last two hours of any road trip to pre-cool the trailer?

I'll second the possibility of leaking duct work. Main or rear heat pump fan, worked itself loose from shaft and ground into the pan on the roof. This was at a rally in Shawnee, Oklahoma. Coleman was there and repaired it for us and inspected the duct work and found a lot of big gaps in the aluminized fiberglass material at the intake and output vents that formed the duct work, from the factory. Cold air was being produced and then immediately reentered the intake and also the roof area though the gaps as were the output vents.. cooled a lot lot better after that. 2010 I think.
If you have 48 degrees chilled air coming out and the duct work sound, then the capacity, the amount of air it cools is not near enough.
A higher capacity and or a second unit seems to be in order.
I have read a number of post over the year about the shoddy put together duct work problems in more than one brand. I never investigated but wonder if there are other gaps directing the cold air into the roof area and not into the room, like was happening at he intake and the output vents.

[ktmrfs]

there are a couple of easy things to do that will help.

1) if you have a ducted system, remove the ceiling vents and use foil tape to close any holes between the duct and the ceiling. More than likely there will be an airspace that needs sealing.
2) take down the AC cover on the inside and tape up any leaks between the AC unit and ductwork. Again, likely holes that need to be closed.
3) Usually there are only a few air vents in the ductwork. The ducts also tend to run the length of the trailer. Once you know where they are, get a holesaw and some more vents and add them in. I added 3 more in our main living area, one in the bathroom and one more in the bedroom. The increase in ducts reduces backpressure on the blower allowing more airflow.
4) I tossed the factory ceiling vents and went for Aireoport vents (amazon) the difuse the air horizontally, have minimal restriction, and are easy to adjust

With all these changes initial temps that had the AC running constantly then had the AC cycling at maybe 50%.

Still need more AC when it nears 100 and we are in the sun, but made a dramatic improvement.

[pianotuna]

Bob,

I suspect the duct work may be "leaking" cold air into the roof (assuming it is a ducted unit).

If you have a generator--perhaps run it for the last two hours of any road trip to pre-cool the trailer?

[NRALIFR]

That IS reasonable temperature drop.

The way I do a quick check of how my air conditioner at home and in the RV is performing is to measure the temperature of the air going into the unit at the air intake filter (not the outside ambient temperature) and at the air outlet register closest to the unit. If I don’t see at least 15 and hopefully closer to 20 degrees of temperature drop, I call a service tech to check it out.

Your air conditioner is only able to displace a certain amount of BTU’s of heat. If the BTU load from outside is higher than what your air conditioner can displace, you reach a point where even with it running 100% of the time it can’t bring the inside temperature down to the same point it could when the outside temperatures were milder.

:):)

[BobsYourUncle]

I just stuck my digital meat thermometer probe into 2 outlets and the reading is 48F.
Don't know what it should be but this seems reasonable.

[down_home]

Bob it seems you are just trying to get by, and you will never get cool, in high heat.
$600.00 for larger unit will help changing to 50Amp is not that hard if you have done it. Total $1000.00-$1500.000I think for an additional unit and conversion to 50 amp. I don't know anyone where you are at but in Kingman, Az I do. I and others sent him so much business, it might take a bit for an appointment.
Like I said our Mh was 50 amp of course, 39 ft two units and with installation of new higher output unit in front location, in Kingman,Az heat, we sat there for a year on a family mission with temps after the replacement of 72 degrees in the heat of 103 to 113 on a few occasions in 2019-2020. Bob I do not BS!
On edit correct the math...
A higher output unit that won't overload your 30 amp circuit with every thing else running will help and more than you think.
Gog to 50 am means a new 50amp controller/charger/converter.Everything can be wired, in all probability to one 50 am leg, a second heat pump/ac to the other leg. Might mean snaking wiring from charger converter to second a/c. and of course a new 50 amp cord from control center/charger/converter and new 50 amp outside cord.
Two ways to fix a problem, yourself or an expert and you pay for it to be done.
You want cool/cold air in the southwest either this or go up high to Flagstaff and north.
You have a fine a really nice unit but it's a/c or heat pump was not designed with the southwest deserts in mind!

[BobsYourUncle]

okhmbldr wrote:
B Y U,
Have you thought about just getting a 12,000 btu portable A/C unit. They may not be as readily available in your area, but I picked one up on Craigslist for $150 about five years ago. Works great and gives the added boost of cool air when needed. I've loaned my to several people when their A/C quit and they were all grateful to have the little unit.

Never thought about that, but don't think I'll get too worried over it. I was more concerned that maybe my AC was heading south. But with the help of you guys here, I think it's acting normal.

Although we get temperatures in the 30'sC / 90'sF, it isn't as frequent as say the southern states such as Florida.

Think I'll climb up top now and pull the cover off to have a look. And clean the inside filter.

Thanks.

[smthbros]

I find summer design temps of 91 at Kamloops and 89 at Trail. Since you are at 94 and maintain 76 indoor, my conclusion is your AC is sized about right. Of course there is also the latent heat load. Are you monitoring indoor relative humidity?

[okhmbldr]

B Y U,
Have you thought about just getting a 12,000 btu portable A/C unit. They may not be as readily available in your area, but I picked one up on Craigslist for $150 about five years ago. Works great and gives the added boost of cool air when needed. I've loaned my to several people when their A/C quit and they were all grateful to have the little unit.

[BobsYourUncle]

TT is 30A, so that's what we are hooked up to.
Oddly enough, there is no roof vent in the main living area, only one in the bedroom at the front, and of course 1 in the bathroom. I have Maxxair covers on both, and one of those cushion plug things to block the bedroom vent. FF in the bathroom. The skylight over the tub is tapered, hard to plug it. We keep the bathroom door closed.
No provision for a second AC.

They didn't "cheap out" with this unit. The build quality is the best I have ever owned in any RV. PCW in this era was known for a good solid build.

I try to keep the awning out, but have to retract it when the wind picks up. Putting a slide awning on is a good idea, I have meant to do that, but havent got to it yet.

Might go up there today and pull the cover off to see if it needs cleaning in there, I know the inside filter is dirty.

The vents can all be rotated and closed off if need be. I adjust to suit.

Thanks again everyone for all the input. May not see the sun today. The smoke is so thick I can chew it....

[dougrainer]

A 32 foot RV with a slide will still not cool adequately in higher temps with a 15k btu AC unit. It will do better, but not get below 75 degrees in hot climates. You need a extra 13.5 btu AC unit installed. If you only have 30 amp service, you will have to add a 2nd 30 amp cord and 20 amp breaker box to run that 2nd AC. If you have 50 amp service you can add the 2nd AC a lot easier. Doug