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  1. #1
    Join Date
    Nov 2007
    Posts
    5

    Compressor doesn't restart

    New unit, installed last year: Carrier Performance compressor #24APA and a FV4B air handler. Works great except one small glitch: After any sort of service interruption, i.e. power outage durning a thunderstorm, even a momentary flicker, the compressor won't restart. The air handler comes back, but no cooling. One has to switch the breakers on and off, (even though they do not apear to be tripped) and then wait about 10 minutes for the compressor to reset itself and come back on line.

    Is this a common problem with the controls on these units? Is there a work around? If you're away on vacation and this happens, you loose the A/C until you return. This can get real ugly real fast here in South Florida.

  2. #2
    Join Date
    Mar 2001
    Location
    North Carolina
    Posts
    428
    This is due to a 5 minute time delay built in the unit to keep it from short cycling, if left alone it should start back up after 5 minutes. when waiting for 5 minute delay it seems like 10 minutes

  3. #3
    Join Date
    Nov 2007
    Posts
    5
    Thanks OBXTECH. I'm aware of and can live with the delay. It's the no restart ever after any kind of power interruption unless I am at home to switch the breakers on and off that's the problem.

  4. #4
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,283
    Quote Originally Posted by obxtech View Post
    This is due to a 5 minute time delay built in the unit to keep it from short cycling, if left alone it should start back up after 5 minutes. when waiting for 5 minute delay it seems like 10 minutes
    That is, if a five minute delay is in place. If the system uses a mercury bulb thermostat and has no delay installed in the outdoor unit, a blip in power supply can cause a recip compressor using only a PSC to stall due to the pressure difference between suction and discharge sides of the pump. It then trips on internal overload and will not restart until the overload cools and resets. Normally, on PSC recips with fixed restrictor metering at the evap, the off cycle equalizing of refrigerant pressures is enough to let the compressor restart on the next call for cooling. With a brief power blip, if the thermostat is calling for cooling, the compressor will try to keep running when the power stabilizes. With no start capacitor and potential relay in place, a recip compressor will likely stall and then trip out on IP.

    For the OP...you can either get a five minute time delay installed via upgrading your thermostat to a model that includes this feature, or have a technician install a delay inside the outdoor unit. A start assist kit would also help, but the delay is preferred if your system otherwise does not need a start assist kit. Personally I prefer a delay-on-break timer at the unit, as thermostats with battery backups may not sense a loss of 24 volt power and activate the delay feature in the stat.

  5. #5
    Join Date
    Nov 2007
    Posts
    5
    Thanks shophound. Unit is new, and thermostat has a programable time delay with battery back up. After a power interruption and timed delay, stat will call for cooling but compressor is locked out and will not reset or restart without the breakers for the airhandler back at the panel being switched on and then off.

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,712
    What does your contractor say about the problem?
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  7. #7
    Join Date
    Mar 2005
    Location
    Houston, Texas
    Posts
    11,847
    Quote Originally Posted by SVWillow View Post
    Thanks shophound. Unit is new, and thermostat has a programable time delay with battery back up. After a power interruption and timed delay, stat will call for cooling but compressor is locked out and will not reset or restart without the breakers for the airhandler back at the panel being switched on and then off.
    Sounds like it's time for a hard start kit. Make sure the put in a quality one.

  8. #8
    Join Date
    Mar 2001
    Location
    North Carolina
    Posts
    428
    COMPRESSOR THERMAL CUTOUT OR LOSS OF 230V
    POWER

    If the control senses the compressor voltage after start--up, and is
    then absent for 10 consecutive seconds while cooling demand
    exists, it will de--energize the compressor contactor, keep the
    outdoor fan operating for 15 minutes (if 230v power present) and
    display the appropriate fault code. Possible causes
    are compressor internal overload trip or loss of high voltage
    (230V) to compressor without loss of control voltage.

    After a 15 minute delay, if there is still a call for cooling, the
    compressor contactor is energized. If the thermal protector has
    not re--set, the outdoor fan is turned off. If the call for cooling
    continues, the control will energize the compressor contactor
    every 15 minutes. If the thermal protector closes, (at the next 15
    minute interval check), the unit will resume operation.
    If the thermal cutout trips for three consecutive cycles, then unit
    operation is locked out for 4 hours and the appropriate fault code is displayed.

    have your tech interupt the power to the unit while its running and see if it is working like it says above. if not he should be able find and repair the problem. this is from the instructions to that system.

    DO NOT PUT A HARD START ON.

  9. #9
    Join Date
    Mar 2005
    Location
    Houston, Texas
    Posts
    11,847
    Quote Originally Posted by obxtech View Post

    DO NOT PUT A HARD START ON.
    Not trying to be a wise a$$, but why not?

  10. #10
    Join Date
    Mar 2001
    Location
    North Carolina
    Posts
    428
    Quote Originally Posted by the dangling wrangler View Post
    Not trying to be a wise a$$, but why not?
    Because it is a new system with a scroll compressor and it does not need a hard start kit. if you read above the sequence of operation at a break of power to compressor, the contactor is most likely not even being re energized by the control board if it is not working as stated above the compressor is not even trying to run so what good would a hard start do anyway?
    It sounds more like a bad control board or not allowing enough time to run through the sequence above. after not starting for 3 consecutive tries.it locks out for 4 hours then starts all over again.

    as stated the system starts up fine after reseting breakers, so that tells me the compressor is starting fine.

  11. #11
    Join Date
    Mar 2005
    Location
    Houston, Texas
    Posts
    11,847
    Quote Originally Posted by obxtech View Post
    Because it is a new system with a scroll compressor and it does not need a hard start kit. if you read above the sequence of operation at a break of power to compressor, the contactor is most likely not even being re energized by the control board if it is not working as stated above the compressor is not even trying to run so what good would a hard start do anyway?
    It sounds more like a bad control board or not allowing enough time to run through the sequence above. after not starting for 3 consecutive tries.it locks out for 4 hours then starts all over again.

    as stated the system starts up fine after reseting breakers, so that tells me the compressor is starting fine.
    OK . I remember installing a few A-S Trane units with scroll compressors, that had start kits installed at the factory, what gives?

  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,712
    Start kit can bump the SEER a tad.
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  13. #13
    Join Date
    Mar 2001
    Location
    North Carolina
    Posts
    428
    Quote Originally Posted by the dangling wrangler View Post
    OK . I remember installing a few A-S Trane units with scroll compressors, that had start kits installed at the factory, what gives?
    Whats with the hardstart kick?

    I was simply stating that it did not need a hardstart kit.
    as he stated it starts fine when he resets breakers and starts it up

    I wasn"t saying because it was a scroll not to put one on i was saying that its not the problem ok?

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