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  1. #1
    Join Date
    Sep 2003
    Location
    Portland.OR
    Posts
    316

    R404 WALKIN FREEZER at Zero degrees

    OK GUYs , HAVE A R404 WALKIN FREEZER at Zero degrees,THAT HAS A FROZEN DRAIN.

    RDI made PR199LOP REF no 0316106. Customer has No tech info.

    Do these units have a defrost cycle?? heater in/around the pan?
    I'd think so.. But have no experience on these systems. Just applying some VERY Simple logic...[maybe]

    THE EXPANSION VALVE IS 2" IN white ICE along with that side of the coil
    .. wATER DRIPS DOWN FROM THE DRAIN and freezes in strings. So if there is liquid water it must be defrosting sometime but the plugged drain is causing
    the overflow
    Its holding "o" temp so freon would be OK it seems. I havent investigated
    the pressures yet.. [roof unit]
    .. THE HEATER cord ALONG THE DRAIN IS WORKING. Of course there is
    no access to the drain outside of the walkin box and it goes in the wall.
    So I figured I'd get some hot water into the plastic drain pipe to get it started opening up I hope.. Its 6 years old
    no maintenance.

    Start with customer moving 1000 pounds of food to get the ladder up there.

    How am I doing so far?

    Looked here:XXXXXXXXX
    and see that there is a defrost[or should be a] cycle.

    So I should force that/confirm its working and get the drain unplugged/unthawed huh...defrost timer would of course be on the roof .

    How often should it come on, and for how long? I want to confirm/change
    the defrost timing
    Better huh?
    thanks guys
    Last edited by Dad; 12-19-2010 at 03:11 PM. Reason: removed unwated site link

  2. #2
    Join Date
    Jan 2005
    Location
    Veterans Home Yaphank, NY
    Posts
    2,309



    Now that we got that out of the way, you MUST get to the unit and cycle it to defrost. However remove the wire from the "X" terminal (defrost termination solenoid)as this will allow it to remain in defrost until all the ice has melted.
    The defrost heater's bottom coil should have a slight bend inot the drain to keep it clear. I've also used a Shark steamer to help defrost the coil.
    Once defrosted re-connect the wire on the "X" terminal.
    Install gauges and check pressures also check amperage both start and run as well as voltage.
    Give us the whole picture and before you know it you too can be a Technician
    RAM Teaching Tomorrows Technicians Today.

  3. #3
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,692
    how bout a drain heat wire in or on the pipe itself?

  4. #4
    Join Date
    Jan 2005
    Location
    Veterans Home Yaphank, NY
    Posts
    2,309
    Quote Originally Posted by Southern Mech View Post
    how bout a drain heat wire in or on the pipe itself?
    O/P states the heater tape along the drain is warm.
    RAM Teaching Tomorrows Technicians Today.

  5. #5
    Join Date
    Mar 2007
    Location
    wedged in freezer shelf
    Posts
    7,215
    How about pitch? Insulated pipe?
    Plastic sucks IMO
    So does fixing drain lines in freezers
    That ice on the TXV does not sound "normal"
    “If You Can Dodge A Wrench You Can Dodge A Ball”

  6. #6
    Join Date
    Dec 2008
    Location
    Nor•Cal
    Posts
    221
    On wif's the txv is often in an area away from defrost heat, in an area with a cover over it. After melting the ice, make sure the cover is installed properly so that humid air doesn't get into that area. That will help, but you also need to do what icehouse said regarding operating conditions. Also if you have melting condensate migrating from the suction line (possibly from outside of the box), that can be a problem.

    Oh yeah - clear all the crud out of that drain line. N2 blast.

  7. #7
    Join Date
    Jul 2010
    Location
    So-Cal
    Posts
    587
    You can use hot water to melt the ice (probably be faster). Then check your defrost heater in the drain pan OHM it.. Blow out the drain..Check your defrost clock is working. They are usually set around 30min 4 times a day.

  8. #8
    Join Date
    Jun 2009
    Location
    DFW, TX
    Posts
    683
    My way of thinking is, if the evaporator is not frozen, then its not a defrost clock issue. What is the purpose of manually defrosting the evaporator if evaporator is not iced up? Why check pressures, compressor amp draw? The freezer is at 0 degrees.

    Drain line heaters usually are powered all the time, or sometimes tied in to run with the refrigeration (typically terminal 4). Drain Pan heater, if it has a separate heater, will energize during defrost. If the drain pan is a block of ice, I'd ohm the drain pan heater if it has a separate one. If it has the bottom row of heaters bent to where it touches drain pan, confirm that it is there and melting the ice as it should.

    REGARDLESS, a frozen drain line means that the drain line is almost surely cracked since water expands when it freezes. Therefore, I would give a quote to replace entire drain line with copper, new drain line heater wrapped around the pipe, and new insulation. While replacing drain line I would confirm proper pitch, etc.

    Of course it's not a bad idea to inspect defrost clock and sight glass on roof, but a frozen drain line is more of a hardware issue than a refrigeration issue in my opinion, especially since freezer is at temp.

  9. #9
    Join Date
    Jan 2005
    Location
    Veterans Home Yaphank, NY
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    2,309
    Quote Originally Posted by trippintl0 View Post
    My way of thinking is, if the evaporator is not frozen, then its not a defrost clock issue. What is the purpose of manually defrosting the evaporator if evaporator is not iced up? Why check pressures, compressor amp draw? The freezer is at 0 degrees.

    Drain line heaters usually are powered all the time, or sometimes tied in to run with the refrigeration (typically terminal 4). Drain Pan heater, if it has a separate heater, will energize during defrost. If the drain pan is a block of ice, I'd ohm the drain pan heater if it has a separate one. If it has the bottom row of heaters bent to where it touches drain pan, confirm that it is there and melting the ice as it should.

    REGARDLESS, a frozen drain line means that the drain line is almost surely cracked since water expands when it freezes. Therefore, I would give a quote to replace entire drain line with copper, new drain line heater wrapped around the pipe, and new insulation. While replacing drain line I would confirm proper pitch, etc.

    Of course it's not a bad idea to inspect defrost clock and sight glass on roof, but a frozen drain line is more of a hardware issue than a refrigeration issue in my opinion, especially since freezer is at temp.
    Ice around the expansion valve is more than a drain problem.
    Don't check pressures, amperage, running conditions ? Sign of "Bubba's" Service.
    RAM Teaching Tomorrows Technicians Today.

  10. #10
    Join Date
    Jun 2009
    Location
    DFW, TX
    Posts
    683
    Quote Originally Posted by icehouse View Post
    Ice around the expansion valve is more than a drain problem.
    Don't check pressures, amperage, running conditions ? Sign of "Bubba's" Service.

    Good idea, running conditions may not be perfect, and at the very minimum that needs to be documented on the invoice. Better to check it to cover yourself.

    Yet I still think the frozen TXV did not cause the crappy PVC drain line to fail. I'd be more inclined to believe that a drain pan full of water contributed to excessive humidity in the evaporator coil which led to ice accumulation on TXV and U-Bends since these areas have no airflow and do not defrost well.

    And as I said, regardless, the frozen drain line will have to be replaced. Yes, original post said heater working. So what? Installation manual says freezers use copper drain lines. So I'm not going to try to tweak the TXV superheat until customer has approved my estimate to replace the drain line and insulate it properly. (Since this has to be done regardless).

    But I agree with you, once the drain line has been repaired, it would be smart to thoroughly inspect the system to notify the customer of any other potential issues.

  11. #11
    Join Date
    May 2000
    Location
    Monmouth Junction-NJ-USA
    Posts
    6,040
    Quote Originally Posted by fixitguy View Post
    OK GUYs , HAVE A R404 WALKIN FREEZER at Zero degrees,THAT HAS A FROZEN DRAIN.


    Start with customer moving 1000 pounds of food to get the ladder up there.
    Did the freezer look like this???


    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

  12. #12
    Join Date
    Jul 2010
    Location
    So-Cal
    Posts
    587
    O/P said the drain line heater is working so I don't think the drain is cracked!!

    I'll bet the drain is just stopped up.. defrost the pan and blow out the drain.

  13. #13
    Join Date
    Jan 2005
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    Veterans Home Yaphank, NY
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    Quote Originally Posted by rayr View Post
    Did the freezer look like this???


    How many times have I seen this in my 40 + years of servicing.
    Last edited by icehouse; 12-20-2010 at 02:23 PM. Reason: Though I teach, still can't spell. LOL
    RAM Teaching Tomorrows Technicians Today.

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