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  1. #1
    Join Date
    Jun 2013
    Location
    So. Cal
    Posts
    58

    RDI low refrigerant flow

    Got an RDI (manitowoc) PCL0127B indoor coil, PCL149M outdoor unit, CF04K6E-TF5-270 comp, Poe oil. Originally R22 but converted to r404 at some point. Walk in cooler supposed to be 34*. Customer called and said its warm. I get on site and its in 2 hour defrost supposed to be at 3am but its noon. Reset defrost timer, unit kicks on and pulls down from 55* to 34* in about 10 minutes. Pop doors open and let it warm up and pull back down, put a done stamp on it and roll out.

    Call back this morning with same issue getting warm. I get on site and check it. Unit running, box at 60*, 9lbs sp, 170lbs hp. Sight glass has trickle going bye it. Try cycling unit, adjust txv in and out, check LL solenoid. Finally I turn off cond, call for cooling, let system equalize, turn cond on and system fires up 50ish lbs sp, 240ish lbs hp, unit cooling. Figured something getting stuck in txv so pump it down, change txv, LL solenoid, and filter drier. Pressure test, evac down to 500 microns, open up LL valve and fire it up. Unit starts up and pulls down to 5lbs sp, 170lbs hp, now it's cycling on lp switch. Try adjusting txv in and out with no success. Packed up and left cause it was getting late. So am I plugged up in the distributor or what? Headed back in the AM to keep pluggin away on it.

  2. #2
    Join Date
    Apr 2013
    Location
    Northern Kentucky/Greater Cincinnati, Ohio
    Posts
    18
    Quick question, were you cycling on your low pressure switch before you did all the changes? Might want to check and make sure your solenoid is not leaking by or your compressor may not be holding the pump down.

  3. #3
    Join Date
    Jun 2013
    Location
    So. Cal
    Posts
    58
    System would run continuously. Comp held pump down

  4. #4
    Join Date
    Jun 2009
    Location
    DFW, TX
    Posts
    569
    Does the sightglass indicate that there is moisture in the system?

  5. #5
    Join Date
    Jun 2013
    Location
    So. Cal
    Posts
    58
    Quote Originally Posted by trippintl0 View Post
    Does the sightglass indicate that there is moisture in the system?
    No

  6. #6
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,307
    Quote Originally Posted by Aaronn View Post
    . I get on site and check it. Unit running, box at 60*, 9lbs sp, 170lbs hp. Sight glass has trickle going bye it. .
    Why a trickle?
    Officially, Down for the count

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

    It was working when I left...
    Liberalism-Ideas so good they mandate them

  7. #7
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,307
    Does this unit have a headmaster?
    Officially, Down for the count

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

    It was working when I left...
    Liberalism-Ideas so good they mandate them

  8. #8
    Join Date
    Jun 2013
    Location
    So. Cal
    Posts
    58
    Quote Originally Posted by 2sac View Post
    Does this unit have a headmaster?
    Yes. When the issue is present there is no heat going into condenser. Pretty much all bypasses into receiver.

  9. #9
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,307
    The headmasters job is to keep the head pressure at whatever rating it is stamped for. It's going to try and do this no matter what the ambient. It also has no idea how much refrigerant is in the system. So, you need to ask yourself why is there a trickle going thru the sight glass. Back to basics.
    Officially, Down for the count

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

    It was working when I left...
    Liberalism-Ideas so good they mandate them

  10. #10
    Join Date
    Jun 2013
    Location
    So. Cal
    Posts
    58
    Headmaster is not going to restrict flow? It's bypassing condenser and dumping right into receiver?

  11. #11
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,307
    If the unit is properly charged, during the summertime, and the headmaster was bypassing, your head would trip the HPS.
    Officially, Down for the count

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

    It was working when I left...
    Liberalism-Ideas so good they mandate them

  12. #12
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,307
    They fail open or closed. Yours sounds like its attempting to keep the head pressure up. They do not restrict flow, just redistribute it.
    Officially, Down for the count

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

    It was working when I left...
    Liberalism-Ideas so good they mandate them

  13. #13
    Join Date
    Jun 2013
    Location
    So. Cal
    Posts
    58
    So where do I go from here. There doesn't seem to be any adjustment for headmaster. Sound like a low charge? Just strange that it was working and cooling intermittently.

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