Norlake walk in freezer
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  1. #1
    Join Date
    Mar 2013
    Location
    Maine
    Posts
    448

    Norlake walk in freezer

    service call to walk in freezer not holding temp today got stumped and frustrated not sure what was going on. upon arrival box 12 degrees
    404a ambient temp 92
    suction pressure 22 = -15 degree evap coil
    liquid line pressure 275 = 110 condensing temp
    compressor drawing 8.4 amps rla 9.9
    superheat 9 degrees
    did not check sub cooling definitely should have
    all fans were running and coils clean
    Box would not pull below 10 degrees
    the unit has a head pressure regulating valve, these always seem to throw me off because if the unit is low on gas it will still hold my head pressure somewhere near where it should be , right? but i had nothing leading me to think it was low on gas because my superheat and suction pressure was within range.
    just looking for some opinions.

  2. #2
    Join Date
    Mar 2013
    Location
    swan valley idaho
    Posts
    718
    at 92 you should condense close to 120, superheat should come down to 5-7,so you may be a little low on charge. try adding a little,sight glass clear?
    -15 evap should pull down to 0-5 box. you should have 10 degree td. you could do a manual pump down and see if compressor is good.close king valve and see how low it pulls and if it holds.

  3. #3
    Yeah, that sounds like low charge to me. That suction and head pressure a little low. At that point the sight glass should be flashing. If it seems clear, close off the king valve and see if it starts to flash off. If not, thatclear sight glass is probably clear with vapor. I would probably add refrigerant to get the pressures up. And find that leak..

  4. #4
    Join Date
    Oct 2011
    Location
    Chicagoland Area
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    4,494
    Did you pump it down?
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  5. #5
    Join Date
    Mar 2013
    Location
    Maine
    Posts
    448
    Quote Originally Posted by 2sac View Post
    Did you pump it down?
    No i didnt pump it down... crap...

  6. #6
    Join Date
    Mar 2013
    Location
    Maine
    Posts
    448
    Quote Originally Posted by big_A View Post
    Yeah, that sounds like low charge to me. That suction and head pressure a little low. At that point the sight glass should be flashing. If it seems clear, close off the king valve and see if it starts to flash off. If not, thatclear sight glass is probably clear with vapor. I would probably add refrigerant to get the pressures up. And find that leak..
    Yeah sight glass was clear but maybe your right , clear with vapor, i added some gas and head pressure didnt move. maybe it was lower on gas than i thought . i thought it could be but im always second guessin myself

  7. #7
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    427
    At 12F box & 9F SH, there is no way your sight glass was all vapor. Follow 2sac's lead. He'll never steer you wrong. Never mind the Al Bundy thing...

  8. #8
    Join Date
    Jul 2011
    Location
    Nanaimo,BC, Canada!
    Posts
    346
    There's two ways a head master ( head pressure control) will fail .. Either it will hold refrigerant back in the condenser to flood it or it will not hold back when it needs to.. In your case if the headmaster was holding back you'd have extremely high head pressure, if it won't hold back then your head pressure will be low in low ambient conditions.. Since you do not have high head then the head master is not holding back .. Like was said front seat the king valve and see if the sight glass falls empty or flashes... Then you're sure you have sufficient liquid at the txv. Then with the sight glass full adjust your SUPER heat to 6-8 f .. Also do the pump down test as indicated above..

  9. #9
    Join Date
    Sep 2004
    Location
    cyberspace, FL.
    Posts
    171
    Quote Originally Posted by northeastbeast View Post
    service call to walk in freezer not holding temp today got stumped and frustrated not sure what was going on. upon arrival box 12 degrees
    404a ambient temp 92
    suction pressure 22 = -15 degree evap coil
    liquid line pressure 275 = 110 condensing temp
    compressor drawing 8.4 amps rla 9.9
    superheat 9 degrees
    did not check sub cooling definitely should have
    all fans were running and coils clean
    Box would not pull below 10 degrees
    the unit has a head pressure regulating valve, these always seem to throw me off because if the unit is low on gas it will still hold my head pressure somewhere near where it should be , right? but i had nothing leading me to think it was low on gas because my superheat and suction pressure was within range.
    just looking for some opinions.
    if your low on charge the head master will be dumping hot gas into the liquid line.......is it real hot to the touch? add a bit of refrigerant and see if it cools down. If so, as previously mentioned, find the leak

  10. #10
    Join Date
    May 2005
    Posts
    1,347
    put it in defrost,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,then take it out of defrost and watch the sight glass..
    if you see bubbles on restart, add some freon..
    Let's give nukes a chance.

  11. #11
    Join Date
    Oct 2003
    Location
    tidewater, va
    Posts
    2,131
    its a norlake, may have cut corners on capacity from day one

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