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  1. #27
    Join Date
    Mar 2005
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    burlington county n.j.
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    9,743
    Quote Originally Posted by mcewans View Post
    I think you can solve this problem by hooking up the C terminal to the common on the 24V. When power is lost, the compreesor is "locked out" and won't start up until the lockout delay in the thermostat is satified.

    any safety or connection after the thermostat could still cause the contactor to chatter, i would still install a time delay at the contactor.

  2. #28
    Join Date
    Jul 2000
    Location
    NW IL.
    Posts
    3,935
    The new scrolls have a thermal relief valve. Once open it does the same thing as a pressure relief allows thermal overload to heat up and shutdown. The overload maybe resetting before the thermal relief closes. Showing no pumping action. Watering down the compressor reset both safeties. Make sure everything is clean. CFM is correct. And heard overcharging will cause the thermal to open as well.
    Aircraft Mechanical Accessories Technician. The Air Force changed the job title to Air Craft Environmental Systems Technician. But I've decided I'll always be a Mech Acc.

  3. #29
    Join Date
    Dec 2002
    Location
    Houston,Tx.
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    16,002
    Quote Originally Posted by GrumpyPawPaw View Post
    If bad valves, it wouldn't have returned to normal pressures.
    Scrolls don't have any valves,at least not like the old recrips did.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

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  4. #30
    Join Date
    Jul 2000
    Location
    NW IL.
    Posts
    3,935
    The Copeland Scrolls will have a decal stating that it has a thermal device.
    Aircraft Mechanical Accessories Technician. The Air Force changed the job title to Air Craft Environmental Systems Technician. But I've decided I'll always be a Mech Acc.

  5. #31
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,563
    The decal is applied to units that have a mechanism that disengages the scrolls from the motor, allowing it to run without moving the scrolls.

    http://www.emersonclimate.com/en-us/...rotection.aspx
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  6. #32
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Quote Originally Posted by timebuilder View Post
    The decal is applied to units that have a mechanism that disengages the scrolls from the motor, allowing it to run without moving the scrolls.

    http://www.emersonclimate.com/en-us/...rotection.aspx
    The scroll mechanism still turns, the ASTP just bypasses the discharge gas internally, which is why no refrigerant is moving through the system when the ASTP is active.
    The bypassed discharge gas trips the thermal overload in the motor windings.
    http://www.emersonclimate.com/Docume...p_overview.pdf

    The compressors listed in the link you posted are commercial AC and refrigeration compressors.
    The K5 scroll compressors used in residential equipment for the past couple of years have a similar feature. I works the same, but has slightly different implementation inside the compressor.
    The previous K3 compressor don't have the ASTP feature.

    I haven't noticed the ASTP warning sticker on a residential unit with a K5 scroll compressor yet.
    If more government is the answer, then it's a really stupid question.

  7. #33
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    18,563
    Quote Originally Posted by mark beiser View Post
    The scroll mechanism still turns, the ASTP just bypasses the discharge gas internally, which is why no refrigerant is moving through the system when the ASTP is active.
    The bypassed discharge gas trips the thermal overload in the motor windings.
    http://www.emersonclimate.com/Docume...p_overview.pdf

    The compressors listed in the link you posted are commercial AC and refrigeration compressors.
    The K5 scroll compressors used in residential equipment for the past couple of years have a similar feature. I works the same, but has slightly different implementation inside the compressor.
    The previous K3 compressor don't have the ASTP feature.

    I haven't noticed the ASTP warning sticker on a residential unit with a K5 scroll compressor yet.

    First I'd seen that internal closeup. Nice.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

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  8. #34
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,097
    Quote Originally Posted by michigan1 View Post
    Its single phase. You mean its running backwards on overload?
    Single phase Scrolls can run backwards if their check valve leaks through, and they have a short power outage and then come right back on.
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  9. #35
    Join Date
    Dec 2002
    Location
    Houston,Tx.
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    16,002
    Quote Originally Posted by beenthere View Post
    Single phase Scrolls can run backwards if their check valve leaks through, and they have a short power outage and then come right back on.

    Yes they will, if you have not personally witnessed this like I have, some might find it hard to believe.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

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  10. #36
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    Is it a heat pump? Not familiar with the model number but if it's a HP, that's a classic reversing valve problem. Little difference or none between high side and low side and a loud compressor!
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  11. #37
    Join Date
    Apr 2004
    Location
    Des Plaines,IL
    Posts
    1,016
    Quote Originally Posted by timebuilder View Post
    That is not what I have seen in the field.

    Of course, the least expensive installer bid for a commercial job means that a C wire is rarely provided, so in that situation, the point is moot.
    I checked, and this works with the FocusPro Series. I am not sure about the VisionPro Series.
    Stuart
    Lack of airflow destroys compressors.

  12. #38
    Join Date
    Jul 2012
    Location
    Phoenix, AZ
    Posts
    40
    You should try and pump down the unit. If the unit doesn't pump down in seconds then its a bad valve.

  13. #39
    Join Date
    Jun 2007
    Location
    NE PHILY
    Posts
    10
    Can this happen if this unit short cycled , example customer playing w/ non digital stat?

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