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  1. #1
    Join Date
    Aug 2012
    Posts
    21

    beverage cooler evaporator freeze up problem

    This customer has a new air cooled condensing unit (4 months old) on this old 2 door glass cooler. critically charged cap tube system. I was called as cooler was warm. found evap frozen solid...I figured it was the cold control as it wouldn't shut the compressor off when i turned the dial...I disabled the compressor to keep evap fan running to defrost...returned and re-enabled compressor and the cold control did turn compressor on (although control wasn't in ice I couldn't turn it off initially)

    Placed guage on suction service port as I wanted to check superheat and I placed other on side to confirm both sides balanced out on off cycle..they were.....

    my question is once system started suction pressure worked it's way to 5-10 psig (R-134a system) so I'm thinking it may be low on charge but suction temp was 43F...am I on right track or what am I missing??

  2. #2
    Join Date
    Mar 2008
    Location
    Chicago
    Posts
    5
    Several concerns, if the evap. Was a block of ice freon charge was probably fine. If you took readings for suction and discharge on a critically charged system you may have lost gas in the process. This could explain slightly low suction press. Temp. Control should be mounted in coil for sensing ice build up. Do the doors seal or does the box get a lot of use? This can cause icing as well. Recommend weighing in the correct charge and putting the temp. Control bulb in the coil.

  3. #3
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,628
    I'm more concerned that you put your guages on. I would have watched the box cycle multiple times with my digital thermometer, and checked line temps before I'd throw guages on a criticaly charged system.

    am I on right track or what am I missing??
    A couple ounces of gas is my guess
    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

  4. #4
    Join Date
    Aug 2012
    Posts
    21
    thanks...for these systems I use seperate guages without hoses, just quick connects so not to lose gas...yes sensing tube is mounted inside coil...it's worked fine for months...it's an older unit that doesnt seal the greatest and it worked fine during the summer where as the location of the condensing unit is above in an attic space that gets very hot...ya I didn't think it would be low on charge

  5. #5
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,628
    I'm lost now. A remote condensing unit with a cap tube???
    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

  6. #6
    Join Date
    Aug 2012
    Posts
    21
    no sorry...the cooler is build into a wall...evap in an insulated box and condensing unit in unconditioned space above..as opposed to most systems we see with everything below that you can remove to work on...this is an old building, with older equipment except for the new condensing unit...

  7. #7
    Join Date
    Feb 2009
    Posts
    134
    5 -10 to Psi indicates low airflow low charge or partially plugged drier or cap tube. Due too hot location of condensing unit and POE oil I would suspect a cap tube problem.

  8. #8
    Join Date
    Mar 2008
    Location
    Chicago
    Posts
    5
    If the attic is hot in the summer it's probably cold now? Low head pressure equals low suction. Where are you located? You may need a fan control.

  9. #9
    Join Date
    Oct 2008
    Location
    Cleveland, Ohio
    Posts
    27
    I have never encountered a remote system with a cap tube. It has to have a txv.

  10. #10
    Join Date
    Aug 2012
    Posts
    21
    yes it's not outdoor ambient cold, but with the summer heat it gets quite warm in the partial attic space it is located......but as it's winter here on the west coast and not below freezing temp isn't affecting the condenser... I thought of a restriction, but the pressure balances out on both sides relatively quickly like you see on properly operating systems...low charge means leak..which my first step is pulling charge and weighing it...thanks guys!

  11. #11
    Join Date
    Feb 2007
    Location
    milford ct
    Posts
    161
    how can you weigh in the charge on a remoted cap tube system ? the unit needs a expansion valve and a receiver and cold controls to work properly
    If a Ram is a Sheep, And an Ass is a Donkey, Why is a Ram in the Ass a Goose?

  12. #12
    Join Date
    Apr 2012
    Location
    winnipeg
    Posts
    1,330
    i concure.....
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  13. #13
    Join Date
    Aug 2012
    Posts
    21
    Sorry guys guess I've confused you. The evap box and condensing unit beside each other above cooler. Can't find a factory charge nameplate. So I was going to pull charge. See what I have. Pressure test. If any leak then ill change dryer and cap tube. If no leak. Re add refrigerant and charge to superheat.
    With the new compressor/ condensing unit, guess leak could be in evaporator. Like I said its old (20yrs or so)

    I was just curious if any of you have come across a senerio like this with suction dropping so much once system starts, but equals with high side when off. I didn't think there would be an obstruction
    I'm just two years in and trying to absorb all knowledge I can!

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