AC won't turn back on

[pspc271]

So I just bought a brand new Sabre 5th wheel. The A\C is blowing nice and cold for a while then shuts off. As as the temp goes up inside the camper you'd expect the unit to kick back on but it won't. The only way I can get it to turn back on is if I set the thermostat to off, wait a few seconds, then go back to cool. Both the front and rear A/C units are doing the same thing. Any ideas?

[fixpro256]

Hi pspc271, Did you get your problem fixed?

[dougrainer]

pspc271 wrote:

dougrainer wrote:

pspc271 wrote:
It's a dometic 12.5 ton AC with a dometic digital thermostat. The camper has 2 air conditioners each with a separate tstat. the front AC is a 15 the back which is acting up is the 12.5. Actually they were both doing the same thing at first. I opened up the front one and it seemed like the foam that was supposed to separate the cold air from the return wasn't wasn't sealed off. After I sealed it off better that unit has functioned properly. I did the same on the rear ac unit but it didn't change anything.

They don't make a 12.5 TON unit. If they did, your roof would collapse:B They make a 13.5k and a 15k. You need to verify that the Freeze Thermister is indeed installed in the coils and the cold air output is not hitting the wall tstat. Doug

Ok you got me, haha. But what exactly is a Freeze Thermister and where would I find it?

The freeze Thermister is installed in the Evap fins. It is about 1 inch long on a white wire. Doug

[pspc271]

dougrainer wrote:

pspc271 wrote:
It's a dometic 12.5 ton AC with a dometic digital thermostat. The camper has 2 air conditioners each with a separate tstat. the front AC is a 15 the back which is acting up is the 12.5. Actually they were both doing the same thing at first. I opened up the front one and it seemed like the foam that was supposed to separate the cold air from the return wasn't wasn't sealed off. After I sealed it off better that unit has functioned properly. I did the same on the rear ac unit but it didn't change anything.

They don't make a 12.5 TON unit. If they did, your roof would collapse:B They make a 13.5k and a 15k. You need to verify that the Freeze Thermister is indeed installed in the coils and the cold air output is not hitting the wall tstat. Doug

Ok you got me, haha. But what exactly is a Freeze Thermister and where would I find it?

[dougrainer]

pspc271 wrote:
It's a dometic 12.5 ton AC with a dometic digital thermostat. The camper has 2 air conditioners each with a separate tstat. the front AC is a 15 the back which is acting up is the 12.5. Actually they were both doing the same thing at first. I opened up the front one and it seemed like the foam that was supposed to separate the cold air from the return wasn't wasn't sealed off. After I sealed it off better that unit has functioned properly. I did the same on the rear ac unit but it didn't change anything.

They don't make a 12.5 TON unit. If they did, your roof would collapse:B They make a 13.5k and a 15k. You need to verify that the Freeze Thermister is indeed installed in the coils and the cold air output is not hitting the wall tstat. Doug

[pianotuna]

pspc271,

Will the rear air conditioner behave if it is run by itself?

[pspc271]

It's a dometic 12.5 ton AC with a dometic digital thermostat. The camper has 2 air conditioners each with a separate tstat. the front AC is a 15 the back which is acting up is the 12.5. Actually they were both doing the same thing at first. I opened up the front one and it seemed like the foam that was supposed to separate the cold air from the return wasn't wasn't sealed off. After I sealed it off better that unit has functioned properly. I did the same on the rear ac unit but it didn't change anything.

[dougrainer]

Need a LOT more info.
1. Does each AC unit have a separate wall tstat?
2. Brand and model of AC unit
3. TYPE wall tstat of AC unit, There are different types each AC brand uses. Doug

[pianotuna]

If it is new, take it to the dealer for warranty repair.

[DFord]

You say it's a new trailer. Has it ever worked correctly?

The air conditioner(s) may have a "freeze-stat" that's not installed as it should be (stuck in the coil fins). When it stops the compressor to let the coil defrost, it's a signal there's something wrong. You have to cycle the thermostat to reset whatever safety device it was that stopped the compressor. Take the filter down and look up inside the air conditioner. If you can see the coil, see if there's anything like a coil of very small tubing hanging in there next to the coil. Also make sure the cool discharge air isn't able to take a shortcut back into the return air.

[pspc271]

I have them set to auto. Its past 2 degrees difference in temp

[rk911]

our t-stat has 3-settings for AC...low, high, auto. low and high will keep the fan running when the set temp is reached while auto will kill the fan when the set temp is reached. and we've found that our system is set to call for heat or cool when there is a minimum of a 2-degree difference between ambient temp and the set temp.

is your t-stat set to low/high or auto? is there more than a 2-deg difference between ambient and set temps?