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  1. #1
    Join Date
    Aug 2010
    Location
    Riverside California
    Posts
    24

    Walk in freezer tripping on over load

    I am working on walk in freezer R404A Air condesing unit ,it was short cycling for 5-10 seconds. The H.p was once 300psi, L.P was 0. upon playing W/ the dual pressure switch ,system would kick in, clean cond coil H.P drop to 200 Psi. Then I close liquid line service valve to pump down system it stops but when I open L.L service system dosent kick in. it only cycles for a few seconds. I changed start and the run capicator . which shorted out the start capicitor again L.P was 115# H.P was 200#.I lowered the S.P and changed the start capicator it still does the same thing. I put TXV bulb in ice cold water as box temp was over 80*. Any advice or assistance would be appreciated. thanks

  2. #2
    Join Date
    Jul 2012
    Location
    Richland, WA
    Posts
    248
    Quote Originally Posted by Qamar View Post
    I am working on walk in freezer R404A Air condesing unit ,it was short cycling for 5-10 seconds. The H.p was once 300psi, L.P was 0. upon playing W/ the dual pressure switch ,system would kick in, clean cond coil H.P drop to 200 Psi. Then I close liquid line service valve to pump down system it stops but when I open L.L service system dosent kick in. it only cycles for a few seconds. I changed start and the run capicator . which shorted out the start capicitor again L.P was 115# H.P was 200#.I lowered the S.P and changed the start capicator it still does the same thing. I put TXV bulb in ice cold water as box temp was over 80*. Any advice or assistance would be appreciated. thanks
    I had one that was doing the same thing and I found that one of the fuses was bad, but that was on a MAC unit.

  3. #3
    Join Date
    Aug 2009
    Location
    Bracebridge, ON
    Posts
    73
    Your potential relay is faulty, contacts are stuck closed.
    Start capacitors are not designed to remain in the circuit for any length of time, if they do they pop.

  4. #4
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    The electrical issue needs to be addressed before you start jacking with the TEV

  5. #5
    Join Date
    Nov 2007
    Location
    Mississippi
    Posts
    1,337
    Liquid line solenoid valve leaking?

  6. #6
    Join Date
    Aug 2010
    Location
    Riverside California
    Posts
    24
    I changed pot. relay and s/c before i turned on i checked l.p 140# and hp 220# decreased lp to 60# ran unit it ran for45 sec and then s/c pop out. changed s/c this time it ran longer than before i checked amps on run winding was11.1 amp and start was 9.1 and common7.6 all this time start winding stays in circuit h.p was 200 and l.p 0 .ohm s-c 3 r-c 1 r-s4

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