Air conditioning cycling on-

[PAylor]

Hi all,

 

We have a two year old Heartland fifth wheel, we're the original owners. We are beginning a big trip that starts our third year of using it. We have done some serious travel in it, probably 40,000 miles, over some arduous terrain.

 

We have two dometic a/c. We decide to get an extension on the original 2 year warranty.

 

Seems like the a/c cycle on more than they should. Could be I'm just paranoid. When I check the thermostat the room temperature is at the set temperature. And it cycles on but the compressor doesn't start.

 

Think I'm facing trouble? Any test you can suggest before it take it in?

 

Thanks in advance.

[MrSeas]

Have you looked at your condenser coils for foreign materials?

[Kirk W]

Seems like the a/c cycle on more than they should. Could be I'm just paranoid. When I check the thermostat the room temperature is at the set temperature. And it cycles on but the compressor doesn't start.

Do you mean that the compressor never starts until you turn it off and back on or that the blower starts when the thermostat isn't calling for cooling so the compressor isn't needed? What thermostat equipment does your system have?

[PAylor]

We have dometic thermostats.

 

And as I said I am probably being paranoid. But it seems to cycle on when the room temperature is close to the thermostat set temperature. It stays on briefly and then shuts off. The compressor does come on when the room gets overheated. I just don't remember short cycles like this.

 

I'll have the hubby check out the coils in the compressor. If anyone has any checks/tests I'd appreciate it.

 

Thanks!

[Kirk W]

There are several different Dometic thermostats and they have a wide range of control functions. Does yours operate normally when it calls for cooling and run for several minutes or more, but only do the short cycle when close to temperature? And are we correct to think that this has only recently started to happen?

[KodiakJack]

We have thermostats #2 and #4 in the photos Kirk posted in our Heartland Landmark. I downloaded the information on #2 so I am most familar with it, though both are suppose to operate in a simlar manner. The AC will operate in a couple different ways depending on how the t-stat is set. If you put the Fan in Auto the AC compressor and fan will come off and on when the temperature hits the set point. If you have the fan in either Hi or Low the fan will run at that speed constantly and only the compressor will come off and on at the set point. So you might want to check how your t-stat is set up. The operating delta (at least for #2) is adjustable to allow either a 1-degree or 3-degree temperature swing with the 1-degree delta setting perhaps explaining your short cycles.

Later,

J

[PAylor]

Kirk, I have number 2. And I don't know if it just started up. I just started noticing it. I think (and hope) it's just me being paranoid. I was just wondering if anyone knew any test we could run to check it.

 

Thanks!

[Kirk W]

If you do not have one, this is the setup instruction sheet for the thermostat that you have and this is a link to Bryant RV's service manual section and a copy of the service manual for that thermostat. I would start by going through the diagnostic process to verify that the thermostat is working properly. If it is, the alternative is to then look at the air conditioner, if you are still concerned. Bryant RV probably has a service manual for it as well, but check there to be sure.