Forum Discussion

hbarker's avatar
hbarker
Explorer
Dec 12, 2020

Air Conditioner does not act right "some times"

Dont know how to explain this but I will try.
Some times our main A/C when set to auto works perfectly.
Room gets cool , Compressor and fan shuts off till temp rises .
Then comes back on when needed to cool room when temp gets over setting. A sit should . AUTO

BUT ,. Some times when room reaches temp setting (say 75) Fan cuts off BUT only for a second. You can still hear the compressor running (humming-growl noise) then then Fan comes back on, Unit will not cycle as it should.
Unplugging the power to the rv and replugging it SOME TIMES corrects it . and Some times it does not .

Am I making any since >?? Something is causing the a/c unit to not work properly on the auto setting ,, But not all the time.

I can set it to Cool, blows constant as it should, and compressor cycles on and off with room temp setting. As it should.

Funny note I might add. This unit has been replaced 3 times under warranty. Yes thats correct THREE TIMES.
  • MFL's avatar
    MFL
    Nomad II
    Dec 12, 2020
    A bit hard to understand, but you do know on auto setting, the fan may stop, choose another setting (high/low), and continue to run, after moments pause.

    Jerry
  • down_home's avatar
    down_home
    Explorer II
    Dec 12, 2020
    Our sensor was near a 12 volt overhead light over rear passenger seat. Sometimes it got really chilly before it shut off. It didn't matter what the thermostat said. It was especially the case hen we replaced the front heat pump with a larger one. And since both units were integrated somehow it could get quite frosty on occasion. Had to keep telling wife to turn that light off, she wanted it on to use her laptop and complained about it being cold all the times wrapped up in a blanket.
  • dougrainer's avatar
    dougrainer
    Nomad
    Dec 12, 2020
    MFL wrote:
    A bit hard to understand, but you do know on auto setting, the fan may stop, choose another setting (high/low), and continue to run, after moments pause.

    Jerry


    Yes, note if fan speed changes when it happens. Replaced 3 times. Because of this? When the upper unit is replaced, that is all that is replaced. The CONTROL system is not touched or replaced. Kind of like having a Engine operation problem in your car and they just replace just the engine. They never touch or look at the controls for the engine. Doug
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Dec 12, 2020
    RV A/C's tend to be noisy Even ducted ones. But here is something you might not know.

    Run the fan on HIGH.. not auto but HIGH.. Yes it will be noisy for a few minutes, then your brain filters the noise.

    What's more when the folks 2 sites over have a knock down drag out with lots of screaming and shouting the "White noise" from the blower blocks it from bothering you (or at least reduces it a bunch)

    In my rig I sat basically under one of my A/Cs and could not even hear it to find out if it was working I had to stand up and listen very closely.
  • chuckbear's avatar
    chuckbear
    Explorer
    Dec 13, 2020
    Our front and rear do the exact same thing. I have replaced the electronics and it did not correct the issue. I recently replaced the thermistor style thermostats with digital ones and the problem has gone away. But we have not used them a lot so time will tell. For years we just never set them to auto and just used the high or low setting. I have hopes this is now resolved. I am pretty sure the issue is not with the AC units themselves. Chuck
  • hbarker's avatar
    hbarker
    Explorer
    Dec 13, 2020
    Thank you guys for the replies.
    Chuckbear : I figured some one would have experienced the same issue.
    I will try replacing my Thermostat asap,

    I should have mentioned , My unit was replaced because it was not cooling properly, not for the current issue,
    When I mentioned it to my rv tech or dealer we could not get it to act up so to speak when they were present.
    The unit still does not cool NEAR AS WELL at the bedroom unit.
    I heard the (because of room size arguments) It just never has cooled properly,

    I can go in the unit anytime hot or cold day , Turn on both a/c units and test with thermometer, Bedroom unit blows WAY WAY WAY Colder than living unit . Always has.,
  • beachcomber_1's avatar
    beachcomber_1
    Explorer
    Dec 13, 2020
    Growling noise from compressor , sounds like compressor fails to star. That noise can occur from start winds failing to turn over the compressor. low voltage or maybe needs a heavy duty start capacitor. Tern on and off allows second restart attempt.
  • dougrainer's avatar
    dougrainer
    Nomad
    Dec 14, 2020
    hbarker wrote:
    Thank you guys for the replies.
    Chuckbear : I figured some one would have experienced the same issue.
    I will try replacing my Thermostat asap,

    I should have mentioned , My unit was replaced because it was not cooling properly, not for the current issue,
    When I mentioned it to my rv tech or dealer we could not get it to act up so to speak when they were present.
    The unit still does not cool NEAR AS WELL at the bedroom unit.
    I heard the (because of room size arguments) It just never has cooled properly,

    I can go in the unit anytime hot or cold day , Turn on both a/c units and test with thermometer, Bedroom unit blows WAY WAY WAY Colder than living unit . Always has.,


    The Bedroom will ALWAYS get colder than the front. The Bedroom turns over the smaller volume of air than the front. Regardless of Ducted or non ducted. Not an argument. Plain FACT. Doug

    PS, this is why some OEM's install a 15k in the front and a 13.5k or a 11k in the bedroom. Saves a little money.
  • JTLance's avatar
    JTLance
    Explorer
    Dec 22, 2020
    Is this a newer Dometic?

    If it is, then its fine!!!! The on and off is when the unit changes FAN SPEED. It will turn off, waits a second, then the fan starts back up. It's 100% normal.

    The reason the thermostat "fixed it" is because the temp changes may be very far apart or stays on LOW much longer.

    Welcome to Dometic.
  • TomG2's avatar
    TomG2
    Explorer
    Dec 22, 2020
    When mine does something similar, it is usually when the outside temp is close to inside. It starts and stops, stutters and blows. I think it has something to do with sensing cool air which starts the fan but stops when it discovers it is just outside temperature. Or something like that. What is the ambient temperature and target temp?

    Mine works perfectly when outside is ten or more degrees warmer than thermostat is calling for.

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