Results 1 to 12 of 12
  1. #1
    Join Date
    May 2005
    Posts
    1,347

    high amp draw on start up

    old customer asked me to look at a freezer that a competitor replaced a compressor on 1-1/2 years ago..

    its been tripping a breaker for a while..i checked the pressures and the amp draw...its a 404 system, running pressure seem ok, lra is 109 and rla is 22, when its running it runs at 15 amp, but on start up it over loads my meter..

    system pumps down ok on the t-stat. when the solenoid opens i can see the liquid line shake and then the pressure rises to start...condensor is on the roof.

    sight glass is full, and the liquid line isn't really that warm or hot when running..


    thoughts?
    Let's give nukes a chance.

  2. #2
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    2,024
    If i do starting amps on any other wire than common it will O.L my meter most the time. Its a UEI meter and dont really know why. I considered starting a thread about it.

  3. #3
    Join Date
    Nov 2009
    Location
    Richmond, working under tarps
    Posts
    483
    what is the supply voltage on start up?

  4. #4
    Join Date
    May 2005
    Posts
    1,347
    my meter is a uei....i checked one leg off of a contractor 230 1 ph..

    indy2000, i didn't check the start voltage..*gulp*
    Let's give nukes a chance.

  5. #5
    Join Date
    Sep 2002
    Posts
    12,195
    Assuming the voltage and start components are good and all the electrical connections, End-To-End, are clean and tight, the first thing I would want to know after that is: is there a pressure limiting TXV or a crankcase pressure regulator installed?

    Can you start the box up warm and measure the amp draw? And if so; can you also trim the amps to FLA by throttling the suction valve?

    Is there a high pressure control? If so; is it manual or auto reset? Maybe the condenser fan occasionally stops running?

    PHM
    ------





    Quote Originally Posted by primmers View Post
    old customer asked me to look at a freezer that a competitor replaced a compressor on 1-1/2 years ago..

    its been tripping a breaker for a while..i checked the pressures and the amp draw...its a 404 system, running pressure seem ok, lra is 109 and rla is 22, when its running it runs at 15 amp, but on start up it over loads my meter..

    system pumps down ok on the t-stat. when the solenoid opens i can see the liquid line shake and then the pressure rises to start...condensor is on the roof.

    sight glass is full, and the liquid line isn't really that warm or hot when running..


    thoughts?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  6. #6
    Join Date
    Jan 2010
    Posts
    6,098
    Single or three phase ?

  7. #7
    Join Date
    May 2005
    Posts
    1,347
    the compressor is a scroll single phase 230 volt.
    no cpr.
    the only time i seen the fans shut down is when the compressor stops..no high psi switch unless i didn't see the little ones they use now..

    breaker is 40 amp..
    Let's give nukes a chance.

  8. #8
    Join Date
    Jan 2010
    Posts
    6,098
    Could be overloading with no cpr or pressure limiting TXV. If its a outdoor unit in a cold ambient it would need some type of head pressure control. If the fan is delaying then there should be a fan cycle switch.

  9. #9
    Join Date
    Nov 2009
    Location
    Richmond, working under tarps
    Posts
    483
    what's the cut in pressure set at?

  10. #10
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,441
    Install a CPR and be done with it!

  11. #11
    Join Date
    May 2005
    Posts
    1,347
    indy2000 cut in was real close to 20 psi..


    thanks guys....
    Let's give nukes a chance.

  12. #12
    Join Date
    Nov 2009
    Location
    Richmond, working under tarps
    Posts
    483
    If supply power checks out, you may need to inspect/install starting components.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event