Installing 2nd A/C Unit

[Johnsonw]

I recently bought a used (2008) 2955RL Montana. It is wired for a 2nd A/C unit. The first warm day, the inside temperature was ~88 degrees F. I turned on the single A/C and while it blew cold air, it seemed to take a while to cool down the unit. I plan on traveling both north and south USA, is it recommended to install a 2nd A/C unit? If so, what size, brand,what do I need to buy and is the install fairly straight forward. Any advice is greatly appreciated.

Thanks
Walt Johnson
(908) 240-9947-cell for those that rather talk than type
johnsonw@merck.com

[Clemson1881]

The Carrier low profile is the lowest height available, and will keep your clearance to a minimum along with reduced wind drag. They also have a slinger that throws the condensation drainage back onto the condenser maximizing cooling and reducing runoff from your roof. Several members have commented that the Dometic low profile units sometimes overfill the drain pan if they are not mounted very level and you get water leaking in your bedroom. The low profile units look better up on the front in my opinion.

[5ER]

If you are going to be in the North during summer you can get by with only one unit but you should start it running before it gets real hot. Also do not use the oven when it is very hot or it will never catch up until late in the evening. We stayed in Wilmington N.C. for 18 months and I was OK with one AC unit but my wife was too hot and had to go back home. Of course I was working and she had to stay in the trailer during the day.

[lasater]

After spending part of last summer in Yuma, I put in a 15,000 BTU Coleman. I really don't need that much cooling but the 2 units together cooled the coach down quickly. During the installation, the outside temp got up over 105 so the inside temp was up there. Once the technicians finished their "in-the-RV-park" installation, Carol turned on both units and went from 105 to 75 in short order. After the coach cooled off, she turned off the original Dometic and ran only the Colemen addon. The 15K BTU kept the coach comfortable.

For your 2955RL, I would recommend the Dometic 13,500 BTU without heating strips. My first Montana was a 2955 that was wired for 30 Amp. If yours is wired for 50, you are OK. If you have a 30 Amp system, you will have to be very careful how you use the 2 ACs. If both compressors start at the same time, I guarantee you will pop circuit breakers.

[Ozz]

I put in a second A/C unit, a 15K, we also get to the site, turn both on, then switch to the bedroom unit and place a small powerful fan on the top steps. I like the idea of the noise upstairs, I have a hard time hearing the TV and conversing with the L.R. A/C on.
Not too much difference between the amp draw of the two available units, why not go with the 15K? The A/C units have a start capacitor that helps on initial amp. surge. also the fan starts then the compressor, so that helps as well. They do what they can to lessen the problem of a high current start.

[KDS MONY]

If you are going to be on 30 Amp service a lot of the time would recommend a high efficiency 13K BTU as the 2nd unit in the bedroom. To help minimize the circuit breaker tripping episodes try leaving one or both of the fans on rather than auto so when the compressor kicks on the fan is already on and there is a slightly smaller surge. We found this to help many times . Best wishes, Jay and Kathy

[clarkandsheila]

We too have a 2955RL with a single a/c. I agree, on what you know or expect to be hot days don't wait untill the trailer is already too warm. Get the unit running much earlier so all it has to do is maintain the lower temp, not dump a lot of built up heat.

I will admit we have to go home before really hot weather arrives. I haven't had to try it in over 90o.

[campbud]

We looked into a Carrier Low Profile Air Conditioner today. We were told that Carrier is no longer making RV air conditioners, they are not going out of business, just no longer making them for RV's ...We were told if something goes wrong we could get parts but if we needed to replace the whole unit, Carrier would just give us back our money. Carrier price wise is the cheaper one, so we are sleeping on it. The Carrier is the lowest profile on the market right now.

[mhs4771]

Keep in mind that not all Air Conditioners will work with all Thermostats. I have read on other posts where you can have problems if you have a central control such as on the newer Montys. I plan to add the second air to my unit, but I will stay with the same as the current unit to avoid any possible problems controlling the units with the common thermostat. These are my thoughts and just something to think about.

[Clemson1881]

If controlling both units from the wall mounted thermostat is important to you then it would be better to go with a matching unit. The Carrier ducted system comes with it's own remote control that handles the thermostat functions. The profile is what I liked about it. Very short and it really helps with clearance issues.

[campbud]

We are going with the Carrier low profile for that reason...the clearance issues. The Carrier will be on its own and not tied into the other air.