High pressure fault in heating

Discussion in 'Maintenance and Troubleshooting' started by Mark Custis, Feb 12, 2014.

  1. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I need some input. I have a WF unit with an ECM blower. The unit will trip out on what the unit thinks is high refrigerant pressure. It only happens during below zero temps here in Cleveland.

    I changed out the coil about two years ago under warranty. I weighed in the charge per the manufacturer's data plate.

    Since the unit is in heating mode the air coil is the condenser coil. I can never catch the unit misbehaving. When I test the unit all numbers are right on the money according to the I/O manual. I am thinking that the ECM may be not moving enough air on long run times.

    I am not sure how to prove my idea short of camping out in the basement.

    Anyone have any ideas or problems with ECM blowers?

    Mark
     
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Might have to put the gauges on and see how high the pressure really is getting.
     
  3. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I have had multiple ECM failures (on a variety of brands) but in no case did it run "some". I'm sure you checked Mark but for others, air filter and duct system would require scrutiny (make sure registers aren't closed in some areas).
    I would change the pressure switch "just cuz". Since you don't have to open the system to t one to the service valve, it's an easy try. Also Ohm out any related thermistors.
    Mark E's geo had a nuisance low pressure lock out and because he is just down the road from me, I was able to camp there some until I finally caught it. With the gauges on and pressure visible, the compressor wouldn't even start because of "low pressure". Usually these stinkers have the courtesy to break completely, but intermittant failures are not uncommon.
     
  4. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Thanks guys.

    I guess I will grab gauges, ohm meter and sleeping bag and head off to Cleveland Heights next cold spell.

    Mark
     
  5. Bergy

    Bergy Member Industry Professional Forum Leader

    Don't forget your Hoodie-Footies!

    Bergy
     
  6. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

  7. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Before camping in basement consider deploying a current or power logging instrument. Compressor current (amps) varies in direct proportion to discharge pressure.

    Another option, likely cheaper, though somewhat indirect, would be to deploy a temperature logging instrument on either or both of compressor discharge line or leaving air.
     
  8. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Curt:

    Great ideas both. Thanks.

    I found a bunch ECM for dummys stuff. It is a start. I have a newer FieldPiece, but not the Data Logger model.

    Our weather has me thinking about a road trip to your home.

    warm regards,
    Mark
     
    Last edited: Feb 17, 2014
  9. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    I have had molex plugs come loose on the CM units in the past and fan would run and always fail when i was not there, finally I found the loose connector and fixed a non issue since
     

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