Best RV air conditioner

[sanda]

My air conditioner on my 30' TT has never been adequate since new. I need to replace it with a better unit. What has been your experience with different units? I am leaning to a 15,000 but need something that will at least cool us 15 degrees below ambient.

 

[Rich W.]

The Dometic 15k btu unit sans heat pump is $1200. With heat pump $1750. 30’ is a lot of space for one AC and 15k is probably the best you can do.

 

[sanda]

Yes 30 feet is asking a lot. I did a 4 hour test of the Temps directly out of the unit and found initially 69 degrees but it slowly increased to 80 and stayed there. Seems the compressor must be going out.

 

[Bob K4TAX]

Measurements on our 13K BTU with 85-degree intake has 58-degree duct temp. Without making intake and duct temperature measurements one can not determine if their AC is working properly. A 25 to 30 degree difference is normal. Less than 25 degrees indicates the unit needs service.

While the units are touted as sealed, an HVAC tech can add a Shrader valve and recharge the unit, thus determining if the compressor is working correctly.

Most RVs are poorly insulated and have many air loss areas. The solution is to reduce outside to inside heat exchange. Reflective film on windows, close shades, and minimize door opening allowing hot air in and cold air out. Cold air is heavier than warm air and cold air pours out like pouring water out of a bucket.

Bob

 

[Rich W.]

First thing to do, before condemning the unit, is remove the cover and see if the coil area is dirty. If so clean it and see if that makes a difference. Also check for air leaks from the “sealed” (usually leaky) cold air area to the outside. Theres a thread here somewhere about this.

Also look at the rated RLA (amp draw) on the sticker on the unit and the test the amp draw while its running to make a comparison (see pic). I had one running at really low amperage and that indicated that the charge was gone so the compressor was spinning freely and thus not working hard enough to draw the rated amperage.

Its hard to find an AC contractor that will work on these but if you call around, or better yet if you know someone, have the charge checked as Bob suggests. If its low you can have it charged, but it means you have a leak, and those can be hard to find/correct.

If it‘s clean, sealed, and tests ok, as Bob suggests, cover all your windows when its hot out but also your shower skylight. That really makes a difference in our coach and it doesn't block the view. We had a 30’ Bay Star with one 15k btu AC and it was ok for most areas, but even working properly, it couldn’t keep up with the temps the South (Memphis, Louisianna, South Texas, etc) in August and Sept. Theres only so much the unit can do, especially in a marginally insulated RV.

 

[sanda]

First thing to do, before condemning the unit, is remove the cover and see if the coil area is dirty. If so clean it and see if that makes a difference. Also check for air leaks from the “sealed” (usually leaky) cold air area to the outside. Theres a thread here somewhere about this.

Also look at the rated RLA (amp draw) on the sticker on the unit and the test the amp draw while its running to make a comparison (see pic). I had one running at really low amperage and that indicated that the charge was gone so the compressor was spinning freely and thus not working hard enough to draw the rated amperage.

Its hard to find an AC contractor that will work on these but if you call around, or better yet if you know someone, have the charge checked as Bob suggests. If its low you can have it charged, but it means you have a leak, and those can be hard to find/correct.

If it‘s clean, sealed, and tests ok, as Bob suggests, cover all your windows when its hot out but also your shower skylight. That really makes a difference in our coach and it doesn't block the view. We had a 30’ Bay Star with one 15k btu AC and it was ok for most areas, but even working properly, it couldn’t keep up with the temps the South (Memphis, Louisianna, South Texas, etc) in August and Sept. Theres only so much the unit can do, especially in a marginally insulated RV.

Thanks for the posts. We started using the reflective aluminum car shades years ago. They did make a big difference. Besides the windows we also cover the vents and shower skylight. It did make a difference but now the unit doesn't put out cool air. Yesterday outside temp 100 and unit temp at outlet was 80. Everything in the unit is clean. Just looking for suggestions on a good replacement unit.

 

[Bob K4TAX]

I would suggest some phone work and get an HVAC tech out to check the unit. Regardless of what's been said, they can be serviced. Of course, if it has a major refrigerant leak, it may then be more economical to replace it with a larger unit.

In our case, the 6-year-old unit had lost most of its refrigerant but was still cooling to some degree. We had a local HVAC company check the unit on site. They installed a Schrader (access valve), pulled a vacuum on the system, and added about 1 lb of the correct refrigerant. Total cost $150. It now cools great. If it lasts another 5 years that will equate to $30/year and the unit will be 10+ years old.

Bob