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  1. #1

    Cold Plate Freezer Issue

    Greetings all,

    I just purchased a 1972 GMC Ice Cream truck with a cold plate freezer. The freezer's identification plate had been removed, so I have no idea what brand it is. It has one larger freezer compartment with 3 doors and a small soda compartment.

    We ran it when I purchased the truck and it sounded and looked great. I ran it for a good 6 hours yesterday, and only the first cold plate ever got freezing temperature. The rest of the plates and the piping seemed to be cool, but were not freezing. a thick coating of ice formed on the pipe going in to the first cold plate.

    Do you have any idea what would make only one of the cold plates get so cold and the rest not freeze at all?

    Thanks,
    Melissa

  2. #2
    Join Date
    Jan 2006
    Location
    DFW Metroplex
    Posts
    4,910
    Hi Melissa - and welcome to the site.

    I haven't worked on a truck as old as yours, but I have worked on quite a few cold plate refrigeration systems over the years.

    In my experience, the average truck refrigeration system can take 12 - 18 hours to pull the box temp down to set point. While your particular refrigeration system is somewhat older.....I still think it should be doing a touch more than causing one cold plate to frost over after 6 hours run time.

    I would say 7 out of 10 service calls I've had on a frozen food truck were related to the system being low on charge (2 out of 10 were due to excessive accumulation of frost on the cold plates).

    My best guess is one of the refrigeration lines cracked or a fitting came loose while the truck was in route to your location - the system probably needs to be recharged with refrigerant.......after the leak is repaired.

    I wish you the best of luck in getting your freezer up and running again soon.
    "The problem is the average person isnt tuned in to lifelong learning, or going to seminars and so forth. If the information is not on television, and its not in the movies they watch, and its not in the few books that they buy, they dont get it" - Jack Canfield

  3. #3
    Thanks for replying so quickly.

    If there is a leak, would we have seen any evidence of it? There is no liquid anywhere in or around the freezer that I can tell. Is it possible the last recharge was so long ago that it just needs to be recharged?

    It has stickers on it saying it has Hotshot 414B in it. The stickers look pretty old.

    I really hope it is only the refrigerant and not something more serious!

    Thanks again!

    Melissa

  4. #4
    Join Date
    Jan 2006
    Location
    DFW Metroplex
    Posts
    4,910
    Quote Originally Posted by Hjorrdis View Post
    Thanks for replying so quickly.

    If there is a leak, would we have seen any evidence of it? There is no liquid anywhere in or around the freezer that I can tell. Is it possible the last recharge was so long ago that it just needs to be recharged?

    It has stickers on it saying it has Hotshot 414B in it. The stickers look pretty old.

    I really hope it is only the refrigerant and not something more serious!

    Thanks again!

    Melissa
    Refrigerant is colorless, odorless, and evaporates at very low temperatures - so you wouldn't see a 'pool' of refrigerant around the equipment.

    That said, the refrigerant oil in the system will usually be present around the area of a leak - which can sometimes offer a clue as to where might be a good starting point for the technician in performing a leak check.

    A refrigeration system is sealed, which means there is never a need to simply 'top off' the system once in a while. The only way a unit becomes low on refrigerant is through a loss of refrigerant charge......period, the end.

    I'm not sure where the compressor (condensing unit) is located on your particular vehicle, but most generally they are mounted either above the cab or under the refrigerated box, between the cab and the rear axle. Chances are if the leak occurred while in transport, it would not have been heard or seen by the driver or passenger.

    I want to stress here, I have nothing to base my assumption on regarding the possible repairs that may be needed......I'm simply going off my experience is all. It could be a leak - chances are greater than 50/50 it is a leak - but without actually putting hands on the truck.......

    Finally, I'm not a fan of 414B. My personal choice would be to run R401B (MP66).....I just think it works better than Hotshot.
    "The problem is the average person isnt tuned in to lifelong learning, or going to seminars and so forth. If the information is not on television, and its not in the movies they watch, and its not in the few books that they buy, they dont get it" - Jack Canfield

  5. #5
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    5,967
    X-2
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

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