Results 1 to 6 of 6
  1. #1
    eskimo joe's Avatar
    eskimo joe Guest

    Question Walk in freezer with no LLS



    I WENT TO SERVICE A WALK IN FREEZEER THAT WAS TRIPPING
    THE BREAKER EVERY COUPLE OF DAYS. I NOTICED THE SYSTEM
    HAS NO LIQUID LINE SOLENOID THE UNIT IS CYCLING OFF THE
    PRESURE DIFFERENTIAL SWITCH WHICH IS CONTRLLED BY THE
    BOXES THERMOSTAT. WHAT PROBLEMS IF ANY WILL THIS CAUSE
    I WAS TAUGHT THAT THE SYSTEM SHOULD BE PUMPED DOWN
    BUT OBVIOUSLY THIS WON'T HAPPEN WITHOUT A LLS. THANKS.



  2. #2
    Join Date
    Oct 2001
    Location
    Nottingham UK
    Posts
    5,733
    Rep Power
    51
    Does the system have electric defrost?. With a full evaporator during defrost the suction pressures will be extemely high when the compressor kicks in and may be the cause of the breaker tripping due to excessive current draw.

  3. #3
    Join Date
    Feb 2001
    Location
    USA
    Age
    63
    Posts
    265
    Rep Power
    24
    Personally, I would install a LLS wired in series with the t-stat on its own circuit, and wire the low pressure switch to the condensing unit on a separate circuit... setting the cut-in and cut-out just for the pump down.

    Having the t-stat wired in series with the LPS is redundant. The system probably was originally wired without a t-stat and was controlled strictly by pressure. My personal opinion of having a pressure switch as the main control is that they are only good on fairly constant loads. If you have any infiltration or rapid door opening, a pressure control will cause short cycling... just like you are seeing now.
    :D
    Dean
    Subzero*psia

    Extinction is simply proof of failure to adapt.

  4. #4
    Join Date
    Dec 2001
    Location
    Canada
    Age
    69
    Posts
    53
    Rep Power
    23
    A "new" walk in? I agree with frank and subzero. Install the lls and thermostat. But what is the condensing unit, defrost heaters FLA and breaker size?

  5. #5
    Join Date
    Feb 2001
    Location
    USA
    Age
    63
    Posts
    265
    Rep Power
    24
    Good Show Gibson!!

    That had totally slipped my mind!
    :D
    Dean
    Subzero*psia

    Extinction is simply proof of failure to adapt.

  6. #6
    tom king's Avatar
    tom king Guest
    Frank & Dean you are so right!
    You must have a liq. sol. vlv. wired in series with the room t'stat and defrost timer for pumpdown on a walk-in freezer. Otherwise, the high back pressure on start-up after a defrost will cause the compressor to run outside its designed temperature range and the extremely high back pressure will cause such a load on the compressor that the amps drawn could trip the circuit breaker. Not to mention, the wear, reducing the compressor life.

Similar Threads

  1. walk in freezer refrigeration sizing?
    By trammd in forum Technical Discussions
    Replies: 10
    Last Post: 02-11-2006, 12:56 PM
  2. It's snowing in my walk in freezer!
    By Matt in forum Commercial
    Replies: 19
    Last Post: 14-10-2006, 07:07 AM
  3. Freezer operation in my garage
    By sonjand in forum Fundamentals
    Replies: 5
    Last Post: 02-08-2006, 10:25 PM
  4. please help with Kenmore Upright Freezer
    By lrn376 in forum Trouble Shooting
    Replies: 0
    Last Post: 09-07-2006, 10:40 PM
  5. condensation on light in freezer
    By ice cold in forum Supermarket Refrigeration
    Replies: 7
    Last Post: 20-05-2006, 05:16 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •