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  1. #1
    Join Date
    Jul 2011
    Location
    SLO/central coast,CA
    Posts
    127

    Hussman plus 2 systems service manual

    Anyone has the service manual for hussmann Rack plus 2 systems XPRT 2 Altech controller.
    model S2S-4A7S7S-5B-PLK S# PS2-156-96.

    freezer 404a and there is some issue with iced up in some evap case, koolgas defrost setting at 18 min for 4 times in 24 hr.

    the company i work for just recently took over the store and there is no log from previous maintenance record.
    what is normal liquid level for this system?



    thanks

  2. #2
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,671
    http://www.hussmann.com/SERVICEANDPA...s/default.aspx

    You ought to be able to link around there and find info that you need.

    NOW, Koolgas defrost is an interesting animal and I've got a pretty good test to prove how well it's working.

    Step #1. Clean the coils. No ice left in ANY of the cases in the lineup.

    Step #2. Let it run until you've got a "normal" frost loading on the coil.

    These are prerequisites to doing the test accurately.

    Attach a clamp thermometer to the liquid line leaving the case and allow it to stabilize. This can be done at the cases or at the rack if the piping system permits.

    Start defrost.

    Observe and log temperatures by the minute.

    You'll see a very distinct and predictable pattern. The temperature will hold stable for a minute or two, drop rapidly through the middle of defrost, then rise again towards the end of defrost as the coils clear.

    If that temperature doesn't reach mid-70s to 80 degrees, you're really not getting a good, effective defrost. Find out WHY!

    I've found solenoid valves not opening completely and EPR valves not closing tightly to be very common causes of repeat and un-diagnosed ice-ups.

  3. #3
    Join Date
    Jul 2011
    Location
    SLO/central coast,CA
    Posts
    127
    Thanks for inputs, very helpful.

    4 copeland compressor serving 8 freezer cases 4 door each. defrost can only 1 case at a time, receiver capacity 635 lbs and liquid level at 20 .

    if 2 case at a time there is not enough warm vapor from receiver to defrost.

    sometimes there is rattling noise on solenoid valve like fan blade hitting on the guard.



    Quote Originally Posted by jpsmith1cm View Post
    http://www.hussmann.com/SERVICEANDPA...s/default.aspx

    You ought to be able to link around there and find info that you need.

    NOW, Koolgas defrost is an interesting animal and I've got a pretty good test to prove how well it's working.

    Step #1. Clean the coils. No ice left in ANY of the cases in the lineup.

    Step #2. Let it run until you've got a "normal" frost loading on the coil.

    These are prerequisites to doing the test accurately.

    Attach a clamp thermometer to the liquid line leaving the case and allow it to stabilize. This can be done at the cases or at the rack if the piping system permits.

    Start defrost.

    Observe and log temperatures by the minute.

    You'll see a very distinct and predictable pattern. The temperature will hold stable for a minute or two, drop rapidly through the middle of defrost, then rise again towards the end of defrost as the coils clear.

    If that temperature doesn't reach mid-70s to 80 degrees, you're really not getting a good, effective defrost. Find out WHY!

    I've found solenoid valves not opening completely and EPR valves not closing tightly to be very common causes of repeat and un-diagnosed ice-ups.

  4. #4
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,671
    Quote Originally Posted by cfe View Post
    Thanks for inputs, very helpful.

    4 copeland compressor serving 8 freezer cases 4 door each. defrost can only 1 case at a time, receiver capacity 635 lbs and liquid level at 20 .

    if 2 case at a time there is not enough warm vapor from receiver to defrost.

    sometimes there is rattling noise on solenoid valve like fan blade hitting on the guard.
    This is perfectly NORMAL. You must only schedule one gas defrost at a time.

    That rattling noise might be a check valve and not a solenoid.

  5. #5
    Join Date
    Jun 2001
    Location
    Michigan
    Posts
    12,077
    your looking for that return saturated liquid coming from the defrosting load to reach close to what the saturated dropleg is at. At that point of equal, there is no latent energy left for melting ice.

    This benchmark, this to me is the ultimate idea on diagnosing an incomplete defrost on a hot gas system. It's clear facts. If it's defrosting, it's changing states, it's dropping then climbing then stabilizing. That liquid production out of the defrosting case is providing the liquid to other non defrosting cases. You can know quickly if you have an issue going on. Electric Defrost doesn't provide this, you have to get in and look physically. PIA to me.

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