Results 1 to 8 of 8
  1. #1
    Join Date
    Apr 2006
    Location
    Phoenix
    Posts
    17

    Carrier 50HJQ008-012

    Brand knew units. Found contactors not pulling in. Installed ground at transformer. Units ok for 2 days. Now lock out relay holding out unit, only in the morning. Tech on site cycled power, ran fine all day. Found locked out again the next morning. Anyone come across this condition?

  2. #2
    Join Date
    Sep 2002
    Location
    Hampton Roads, Virginia
    Posts
    1,557
    Check the location of the defrost thermostats, some of the units are coming (from Mexico) with the defrost thermostat mounted on the wrong side of the 'T', look in the IOM for the correct location. Also if two stage unit check that defrost thermostat is mounted on correct coil for the reversing valve it is controlling.

    Kevin
    "Profit is not the legitimate purpose of business. The legitimate purpose of business is to provide a product or service that people need and do it so well that it's profitable."

    James Rouse

  3. #3
    Join Date
    Jun 2006
    Location
    New Jersey
    Posts
    4,289
    Quote Originally Posted by helpaprobie View Post
    Brand knew units. Found contactors not pulling in. Installed ground at transformer. Units ok for 2 days. Now lock out relay holding out unit, only in the morning. Tech on site cycled power, ran fine all day. Found locked out again the next morning. Anyone come across this condition?
    Why weren't the contactors pulling in? Was voltage weak and that's why you thought the transformer needed grounding?

    Tattle tails are your best friend when dealing with carrier rtu's. But they are normally my last resort. Normally I am able to identify a issue, with checking air flow, charge, and operation of cooling components.

  4. #4
    Join Date
    Apr 2006
    Location
    Phoenix
    Posts
    17
    Klrogers thank you. We did not check defrost t-stat to right coil. We are going to check units in the morning.

  5. #5
    Current sensing relay holding out the contactor due to unknown problem

  6. #6
    Heatpumps current sensing lock out relay board locking units out in heating mode early in the morning.

    Transformers tap to correct voltage.
    Liquid line, discharge pressure switches are not opening.
    Pressures appear correct giving the low ambient the unit are working 20

    We reset the units and they run correctly for the rest of the day no other issues with them locking out, next morning units are not heating.

    Defrost board set for thirty minute cycle, space temperate set for 68. Outside air damper closed, no economizer on unit.

    Unit using Venstar energy management system.

  7. #7
    Join Date
    Apr 2006
    Location
    Phoenix
    Posts
    17
    Found 2 issues. Fan limit switch cutting out fan at 90 degrees. Found when unit would go into defrost during the night the 0 degree refrigerant rushed back into the evaporator opening the freezestat causing the lock out relay to open the circuit. THANK YOU ALL FOR THE HELP!

  8. #8
    I am having the same problem. Carrier aquazone - the compressor shuts off early morning during a heat call. Fan continues to run non stop until manually shut off and restarted. Works fine for the rest of the day. I hate waking up freezing!

    This is in a closed loop boiler/cooling tower system in a loft/condo in a renovated historic manufacturing building converted to condos.

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