New AC unit is short cycling

[JConsroe]

I upgraded the heat pump on our 2005 28' international from the stock 13,500 btu up to a 15,000 btu dometic low profile. It worked great when we were in SC and it was really hot. When we reached the coast in NC it cooled off to about 80 degrees. It was still warm enough to need ac for the baby and the dog but the unit short cycles at this temp. It only runs for a couple minutes and then shuts off obviously because it has cooled it down quickly with the added capacity. It also comes back on five minutes later. I experimented with different set points but it doesn't seem to make a difference. Technology in all other airconditioning now days have a veritable capacity compressor. For whatever reason this technology hasn't reached rv ac units in the US yet. Wondering if anyone else has come up with a solution? I know it can't be good for the compressor to start and stop all day long.. Maybe some way to put a time delay in?

[jcanavera]

This is the danger of having too much capacity. I know with ours that the humidity in the trailer starts to rise at night so my thermostat setting doesn't provide the comfort that it does in the day. I usually have to go down a couple of degrees to get a little more run time.

I'm going to assume that you allow the fan to cycle on and off rather than allow it to run continuously. Constant running of the fan will allow the humidity to build up even faster in some cases since the water left on the coils will evaporate back into the trailer make it all the more clammy.

Variable speed compressors that are found in homes usually require DC fan motors that have speeds that vary dependent upon compressor speed, which are very expensive. At this point I'm not sure of the market is there to justify this kind of technology in RV units. In a home unit the major use of these types of ac units is energy savings.

Jack