Dometic Brisk Air air conditioner

[kalia]

First off, my apologies for posting in the wrong place. Here's my post again. Our Dometic Brisk Air air conditioners (13500 just like the one pictured by RobWNY 7/18 along with the thermostat and the other 15000 with the same type of thermostat) turn on and off sporadically & have been doing such for 2 months. These are in our 2018 Jayco Bungelow. Our repair person has called Dometic numerous times and gets a different answer every time. I've even tried calling them and after going through all the details have been told I can't speak with a tech because I don't have an account with them. Fan will shut off for a few seconds, something hums loudly, then fan turns back on. Fan will go from "low" to "low", then "high", then "high", then "high", then "low", etc. This happens no matter what the outdoor temp is. In fact, the 15000 did it one night when the outdoor temp was lower than the indoor by a couple of degrees. I timed the 13500 one night for an hour while in bed. It shut down for approx. 45 seconds, hummed, then turned back on for 2 minutes then repeated. 15000 would do the same thing. Now both are turning off and on in a much shorter time span...1 min. on, 5 seconds off, hum, repeat. We had the fan set on "auto". Thermostat for the 15000 has been changed out...no difference. 13500 has a new electric component box inside...no difference. We're a little edgy sleeping at night and also don't want to go away during the day for a few hours leaving the dog in the unit for fear of a fire. Any suggestions will be deeply appreciated. Thank you all in advance. And I'm going to add... each and every one of you was a rookie at posting at one point in time and I thank those who have offered their sincere help.

[kalia]

Thank you to all who responded with actual help. We appreciate it. Yes, a/c is a Brisk II, we do have the model #s, but will identify the thermostat.
Sadly, we can't plug our unit in somewhere else as we live in a campground, each having our own 50 amp electric post. Also can't move the Bungelow park model.
To Doug: the unit will cool on hi/cool or low/cool. But because the fan is running, it takes a minute to realize that the compressor has shut down, blowing warmer air, and we can't tell if the compressor is humming because of the fan noise. One thermostat is in the unducted hallway across from a picture window. Brilliant planning on the trailer's manufacturer's part. We've been keeping that shade down. The bedroom thermostat is located across the room from the a/c. Will try all suggestions including the digital 120 voltage reading.
Thank you all again.

[dougrainer]

Fan will shut off for a few seconds, something hums loudly, then fan turns back on.

The hum is the compressor---Normal. Doug

[dougrainer]

What happens if you choose HI/COOL? Does the unit then run and cool correctly? It will shut the compressor OFF in this mode when it reaches the cool set temp. If HI/COOL is not acceptable, use LOW/COOL. The way Dometics run can be upsetting if not used to this new models and controls
IF on AUTO/COOL, the unit will go to HI/COOL. I don't have my manual at home, but I believe the change fan speed is 4 to 5 degrees to set point. That means it runs on HI, as it reaches that 4 to 5 degrees the FAN will shut down for 1 second or 2 . THEN start back on LOW. The compressor will stay running. Once the AC reaches set temp, the Fan will shut down and a few seconds later the compressor will shut off. IF you have a problem with where the wall tstat is mounted, like a duct louver is blowing on the tstat, the system may short cycle. Also, the position and mounting of the freeze thermistor is a must. If the AC is NOT mounted correctly, like the baffles and air box is NOT sealed correctly, you will get oddball running like what you experience. Are you on 50 amp service? Can you get a digital 120 voltage reading from a wall receptacle when BOTH AC's are running? Doug

[joshuajim]

I found on my Wildwood that the A/C installer failed to install the freeze sensor into the evaporator coil. It was just hanging loose. You might want to check yours.

[Roger10378]

It sounds to me like the coil is freezing and the unit changes the fan speed to get it to thaw. Mine does what you describe when the weather is hot and humid which we have had a lot of recently. There is also a lot more water coming off the roof when it goes to high speed. It sounds like everything is operating properly.

[Retired_JSO]

What you described is normal. My fan will cycle like you described when set to auto fan and the RV is warmer than 2-4 degrees of thermostat setting. Turn the fan to high or low until the compressor cycles then put the fan back to auto.

[newman_fulltime]

Plug the trailer in somewhere else my bet this problem goes away.As the only thing they have in common together is the ground and neutral wire

[SoundGuy]

kalia wrote:
Our Dometic Brisk Air air conditioners (13500 just like the one pictured by RobWNY 7/18 along with the thermostat and the other 15000 with the same type of thermostat) turn on and off sporadically & have been doing such for 2 months. These are in our 2018 Jayco Bungelow.

First step is to get the model numbers of your A/C units ... since these are on a 2018 trailer they're certainly not Brisk Air units as those were discontinued several years ago, replaced by the Dometic Brisk II. Also identify just which thermostat(s) you have as Dometic makes a couple dozen different versions.

[imgoin4it]

Sounds like the fan is shutting off while the compressor continues to run. If the fan heats up it will shut off due to thermal overload (heats up). It will start again within 2or3 minutes. Mine did exactly as you describe . Mine was caused by a thermostat when a new acnd unit was not hooked up properly. .Dont know what could cause this when nothing was changed, but that sounds like what is happening.

[Lwiddis]

Doesn’t appear closed to me.