A/C acts like power is interrupted

[bob213]

I've gone thru hundreds of posts and can't seem to find any with the same syptoms.
I have a 2012 Surveyor with a Dometic 13.5 A/C unit. It cools fine. It only has a single fan speed and no choice on the themostat. It will be running fine and then suddenly it will sound like it has a momentary loss of power and then resume normally. The interruption is a second or less and then it continues on as if nothing happened. It will run for awhile and then repeat this. Any ideas?

[Herk7769]

Does it run pretty much constantly?
The thermostat might be set too low.
Try setting it no lower than 10 degrees below outside air temp.

[bob213]

Thanks Herk. I'll try that, but since we live in 100*+ temps, that's not going to get us very cool. I will try it just to see if it changes the situation.

[DDC]

Mine does that too, I honestly thought it was just normal it's done that since it was new.

[fonzie]

Could it be that the fan runs constantly and it is the compressor cycling on and off as needed?? That will create what your describing.

[bob213]

Originally Posted by DDC

Mine does that too, I honestly thought it was just normal it's done that since it was new.

That makes me feel alittle better. Since I got a hearing aid I'm hearing things I've never heard before. Maybe I'm just to much of a worry-wart?

[B47]

Originally Posted by fonzie

Could it be that the fan runs constantly and it is the compressor cycling on and off as needed?? That will create what your describing.

I'm betting that's what he's hearing.

[Blaster 84]

Take out the hearing aid and the cycling won't bother you anymore.

[bob213]

Originally Posted by Blaster 84

Take out the hearing aid and the cycling won't bother you anymore.

Have a wife that still hears a pin drop! Then I'd get...YOU can't hear that???

I think fonzie and B47 are correct. Thanks guys!

[Iggy]

Turn the fan to Auto on the thermostat and NOT on High or Low

[Herk7769]

Originally Posted by bob213

Thanks Herk. I'll try that, but since we live in 100*+ temps, that's not going to get us very cool. I will try it just to see if it changes the situation.

Sorry. When temps are over 100 leave the thermostat at 90.

It will run almost constantly when it is that hot in any case.

[Tiggerdad]

Temps. are in the 90's and A/C runs full time mid day as expected. I have noticed that the compressor will sometimes shut off for a split second and begin running again. Fan does not shut off. It just shut off without it restarting immediately but the fan continued to run and I am assuming that the time delay kept it from restarting. It restarted normally. This is the first time it has done that. The unit is a 2013 FR Crusader 33MKS with Dometic 15,000 BTU unit. We have a second 13,500 Dometic that blows out the sides in the bedroom. We run it mid day when the temps. rise and it does not exhibit this issue.

It is a ducted system with 2 return air vents in the ceiling. The area where you normally see the A/C unit is covered above a center island with lights. This prevents me from seeing it the unit is icing up and it has a 1 speed fan. Power is excellent from looking at my A/C meter so I don't believe this is an issue. We are on a 3 week trip and it began this after arriving in this campground 3 days ago. I am thinking this is just a coincidence.

Any ideas?

[TURBS]

Frost sensor detected freezing coils.
It shut the compressor down briefly to thaw then back on.
High humidity and high temps will do that .

Btw perfectly normal.

Turbs

[TURBS]

Two things that may help.

Open quick cool dump during the day vs ducted.
When ducted make sure all vents are completely open .

[bubbles]

I have 2 dometic A/C (13500, 15000) and ocassionally one or the other will do that, shut down for maybe a few seconds and start back up. My previous unit A/C's also did the same thing. Had that unit for 10 years and no A/C issues.

[rip]

Originally Posted by Tiggerdad

I have noticed that the compressor will sometimes shut off for a split second and begin running again. Fan does not shut off...

It just shut off without it restarting immediately but the fan continued to run and I am assuming that the time delay kept it from restarting. It restarted normally. This is the first time it has done that...

Any ideas?

Sounds like you said two things about your compressor maybe?

One, shut off for a split second, fan kept running; two, shut off without restarting immediately, fan kept running, and mentioned time delay.

The latter may be a thaw operation, the former "split-second" blink may be a different issue.

[Tiggerdad]

Does not have a "dump" on it. Completely ducted. I have had the unit for 11 months and spent maybe 60+ days using the AC so this is not normal. This problem began 3 days ago and we have been on the road for 3 weeks with temps. 90+ everyday. I removed the outside cover yesterday and system is well sealed. Exposed evaporate elbows were sweating heavily with no ice so it does not appear to be a icing problem. Water runs off the back of the camper with a steady drip. The shutdown of the compressor for a short period of time started for the first time today. That is what prompted me to pose the question.

Rip, you read correctly. The "split second" was just about that quick. Happens so quick that the only way I noticed it was a sudden change in sound. Unit does not shutdown long enough to do a thaw. Previous rig had a 15,000 BTU ducted that never did this in 7 years. Did pull an amo check yesterday. Unit is pulling just over 15 amps.

[TURBS]

Originally Posted by Tiggerdad

Does not have a "dump" on it. Completely ducted. I have had the unit for 11 months and spent maybe 60+ days using the AC so this is not normal. This problem began 3 days ago and we have been on the road for 3 weeks with temps. 90+ everyday. I removed the outside cover yesterday and system is well sealed. Exposed evaporate elbows were sweating heavily with no ice so it does not appear to be a icing problem. Water runs off the back of the camper with a steady drip. The shutdown of the compressor for a short period of time started for the first time today. That is what prompted me to pose the question.

Rip, you read correctly. The "split second" was just about that quick. Happens so quick that the only way I noticed it was a sudden change in sound. Unit does not shutdown long enough to do a thaw. Previous rig had a 15,000 BTU ducted that never did this in 7 years. Did pull an amo check yesterday. Unit is pulling just over 15 amps.

Ice doesn't build up on outside but rather the inside

[rip]

Originally Posted by Tiggerdad

Power is excellent from looking at my A/C meter so I don't believe this is an issue. We are on a 3 week trip and it began this after arriving in this campground 3 days ago. I am thinking this is just a coincidence.

If you had not said power is excellent, I would have suspected a power problem at your new park. It sure reads like a power spike or low voltage problem. No clue here on my part, my only similar experiences were power related. You likely have a 50 amp circuit coming into your RV, which I also have little experience with concerning the split voltage. Good luck with this.

[Tiggerdad]

Turbo, I know that the ice builds up on the inside but I have seen ice crystal, not a lot, build up on the edge of the exposed coils next to the insulated section.

Anyone have an idea if a run capacitor could cause this problem? I be home tomorrow, I will then have a chance to remove the wooden cover over the inside unit and check to see if perhaps something was in the duct that now is setting against the evaporator or if it is icing up.

Rip, I was in College Station last week. Visited the Bush library.