Poor Air Conditioning performance 8229SB.

[Jim S JR]

Hello All.
Recently purchased a 2020 Rockwood 8299SB 5vr. It came with one Air Conditioning unit in the main living area and appears to be very underrated for the area needed to cool. In my oed 5th wheel, the single unit was sufficient.



It runs all day and doesn't cool very well. I live in the Los Angeles area. The weather has been warm but overall it's doing a very poor job.


Any suggestions? Is anyone having the same problem?


Has anyone installed a second unit in the bedroom and the cost?

[dustman_stx]

Originally Posted by Jim S JR

Hello All.
Recently purchased a 2020 Rockwood 8299SB 5vr. It came with one Air Conditioning unit in the main living area and appears to be very underrated for the area needed to cool. In my oed 5th wheel, the single unit was sufficient.



It runs all day and doesn't cool very well. I live in the Los Angeles area. The weather has been warm but overall it's doing a very poor job.


Any suggestions? Is anyone having the same problem?


Has anyone installed a second unit in the bedroom and the cost?

Turn the unit on high cool and set tstat well below room temp(preferably when it’s 80+ inside the coach and during the heat of the day). Allow to run for 10 minutes. Make sure you have good airflow coming from the vent closest to the return air grille. Check the temp of the air coming out of the vent closest to the return and the air returning at the intake. Don’t use a laser thermometer, you have to use a type the air can move across. I use a digital probe type thermometer and actually place it up in the vent for the best reading. If you’re not getting at least an 18* difference, but preferably 25+, it’s not cooling properly and was either undercharged or has a leak in the cooling system and must be replaced.

[Bama Rambler]

There are many threads/posts about the lack of cooling in RV's. Common issues include plenum partition not in place and/or sealed off between the intake and outlets, Ducts not sealed at the A/C, Terminal ends of ducts open to the attic, ducts crushed and restricting air flow, and several other things. I suggest you look into some of those to see if you have similar issues.

One thing is that a single A/C in a 35' fifth wheel RV is less than adequate. Your RV comes with 50 amp service and is prepped for a second A/C. If I were you, I'd go ahead and add the second A/C to your unit.

[5thwheelinfireman]

X2 on the second AC unit. Camping in GA in summer requires the second unit in the bedroom.

[Jim S JR]

Thank you. Will check the temp on the ducts.

[WannaBcamping]

Is your one A/C unit a 13.5 BTU or 15K?

[TitanMike]

I wasn't totally satisfied with my A/C's performance (a 13,500 btu in a 25'TT) so I pulled the main grille where air filters are mounted. Air filters were clean but inside it appeared that someone got carried away with their can of "Good Stuff foam" When sealing areas that air shouldn't go the excess foam expanded into places where air should go. Namely the in-ceiling duct passages. In my TT there are two duct channels molded into the ceiling structure and both were 50% blocked by the foam overflow. A couple minutes with a cheap steak knife and both duct entrances were clear.

A/C now works great and was able to maintain a comfy 75 degrees when the outside temp was just under 100 degrees.

Also did the same with all the outlets, pulling the louvered covers and clearing excess foam. Not as much but "since I was in the neighborhood".

[Jim S JR]

13.5, seems underated.

[Jim S JR]

Originally Posted by TitanMike

I wasn't totally satisfied with my A/C's performance (a 13,500 btu in a 25'TT) so I pulled the main grille where air filters are mounted. Air filters were clean but inside it appeared that someone got carried away with their can of "Good Stuff foam" When sealing areas that air shouldn't go the excess foam expanded into places where air should go. Namely the in-ceiling duct passages. In my TT there are two duct channels molded into the ceiling structure and both were 50% blocked by the foam overflow. A couple minutes with a cheap steak knife and both duct entrances were clear.

A/C now works great and was able to maintain a comfy 75 degrees when the outside temp was just under 100 degrees.

Also did the same with all the outlets, pulling the louvered covers and clearing excess foam. Not as much but "since I was in the neighborhood".

It sounds Ike just pulling off the filter cover will give me access?


On the registers, how did you get them off?


I've been under the trailer doing work. Had to put a support under the carriage to support the plastic covering. The thing was sagging about 4 or 5 inches. Used a metal door threshold to hold it up. There were 2 gas lines under there and I could see that coming off and riping off those lines.



Also saw an open area where the gas line comes down that could use foam to keep the water out.

[Jim S JR]

Originally Posted by dustman_stx

Turn the unit on high cool and set tstat well below room temp(preferably when it’s 80+ inside the coach and during the heat of the day). Allow to run for 10 minutes. Make sure you have good airflow coming from the vent closest to the return air grille. Check the temp of the air coming out of the vent closest to the return and the air returning at the intake. Don’t use a laser thermometer, you have to use a type the air can move across. I use a digital probe type thermometer and actually place it up in the vent for the best reading. If you’re not getting at least an 18* difference, but preferably 25+, it’s not cooling properly and was either undercharged or has a leak in the cooling system and must be replaced.

Thanks for the feedback, sorry it took so long. The temp coming out is 40, it's 95 outside.
A 13.5 btu is probably underrated for a 35 ft overall 5th wheel. I'm sure the higher ceilings don't help.

[TitanMike]

Originally Posted by Jim S JR

It sounds Ike just pulling off the filter cover will give me access?


On the registers, how did you get them off?



I've been under the trailer doing work. Had to put a support under the carriage to support the plastic covering. The thing was sagging about 4 or 5 inches. Used a metal door threshold to hold it up. There were 2 gas lines under there and I could see that coming off and riping off those lines.



Also saw an open area where the gas line comes down that could use foam to keep the water out.

I didn't take registers off. I did some "surgery" on the excess foam around the registers with a steak knife and then just turned on fan to blow out all the beads.

[Jim S JR]

I have checked the temp again. In 2 hours it went from blowing 40 to 80???

[Jim S JR]

Originally Posted by TitanMike

I didn't take registers off. I did some "surgery" on the excess foam around the registers with a steak knife and then just turned on fan to blow out all the beads.

Thanks Mike, I took off the register and the foam wasn't an issue. But what I did realize is why the A/C isn't cooling well.
There is no duct work in the ceiling. What they have is channels in the foam that the air flows through. With my 35 ft trailer there are 12 vents available. I keep them all closed to keep the major air flow into the main living area and just have the vents on the main unit flowing in.


This is a terrible design. There is all that heat from the roof beating down and warming that air in those channels and having a 13,500 btu unit doesn't help..


The vents are clear to allow flow but it's just too much heat coming into the trailer for the unit to handle and too much room inefficiencies.
Whe i looked into the vents, I can see the foam roofing.

[Jim S JR]

I ran across this item to increase A/C airflow. Has anyone here used the Styrofoam insert recommend?


https://rvairflow.com/

[tmkwasinski]

Saw a uTube video on this. Very impressive. They did a before and after install duct reading which included are flow pressure.
We are giving this serious thought but have to wait for the weather to break to determine if it will work with our unit since we are not listed on their site. Also---pretty snowed in up here.