Results 1 to 13 of 13
  1. #1
    Join Date
    Oct 2002
    Location
    Lexington, NC
    Posts
    5,159

    RTHC Low Differential Rfgt Press-Cold Cond Water

    I have had two faults recently on this unit. One is Low Differential Rfgt Pressure and the other is No Differential Rfgt Pressure. Both faults say that the condensor water is too cold. I have verified that the system bypasses until the return water is in the 82 degree range. I have also turned the fan control to low speed. There is about a 3 pound pressure drop on the condensor water side, and about an 8 degree temp diffence on the chiller condensor supply and return lines. I don't know the conditions when the unit is going down because it seems to be happening at night. the refrigerant level appears to be fine, and varies from -.2 to .5, depending on the EEV position.
    Anything else I can do?
    The main thing is to keep the main thing the main thing!

    If "the grass is greener on the other side", it likely has been fertilized with Bull$hit!

  2. #2
    Join Date
    Sep 2008
    Location
    Texas
    Posts
    371
    You need to install a condenser water regulating valve controlled by delta p between evap and condenser if you don't have it.
    "Dying aint much, its living thats hard." (Josey Whales)

  3. #3
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,081
    RTHC IOM 1C Page 24 tells you how to do it.
    Also RTHC-SVN02C has more info about it .
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  4. #4
    Join Date
    Apr 2004
    Location
    Lombard, IL
    Posts
    29
    Quote Originally Posted by CaptJackSparrow View Post
    You need to install a condenser water regulating valve controlled by delta p between evap and condenser if you don't have it.
    This statement is a must and a fact. With out this regulating Valve you will continue to shut down on this diagnostic. Obviously captain Jack Sparrow works for Trane too.

  5. #5
    Join Date
    Oct 2006
    Location
    Central Texas
    Posts
    638
    The regulating valve will make the problems go away. Curious, what's the ambient temp around NC this time of year? It probably wouldn't hurt get your tower under control. You said the bypass works? Do you know what temp it begins to start flowing through the basin? If it goes over the top in cold weather, you're going trip w/out the valve.
    Sic Semper Tyrannis.

  6. #6
    Join Date
    Oct 2002
    Location
    Lexington, NC
    Posts
    5,159
    Bypass changes over around 82-84 degree water temp.
    The machine may have the valve you are refering to. Do you have a pic of one?
    It is about 55-65 during the day and in the upper 40s at night.
    The main thing is to keep the main thing the main thing!

    If "the grass is greener on the other side", it likely has been fertilized with Bull$hit!

  7. #7
    Join Date
    Sep 2004
    Posts
    175
    I have an account that has 2 RTHDs that need the modulating cond. water valves. I completely forgot all about them. Thanks for the reminder, I think I'll turn in a tech lead.

  8. #8
    Join Date
    Mar 2005
    Location
    Indiana
    Posts
    159
    You may be able to get by with the setup you already have if you can run your condenser water through thr chiller for about 2-3 minutes before you start allow the chiller to start to stabilize the water temp before it starts. The last thing you want to happen is to get the chiller started and the tower water temperature fall. Will trip it out every time.

  9. #9
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,081

    Frown

    This maybe of help too RLC-EB4 RTHC condenser water control .
    I cant figure out how to upload it on here .
    I"m a nuts and bolts guy not a computer guy ???????/
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  10. #10
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,081
    Yee haa I did it . Here ya go.
    Attached Files Attached Files
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  11. #11
    Join Date
    Sep 2008
    Location
    A land down under
    Posts
    311
    RTHC chiller production finished well over 6 years ago. Seems kinda strange for one without proper CW control to operate this long and not have heaps of ongoing differential pressure diagnostics. Anyway not my place to question RLC-EB4 no longer attached
    Last edited by Screwit; 11-17-2009 at 09:51 PM. Reason: removed RLC-EB-4 Graham figured it out

  12. #12
    Join Date
    Apr 2009
    Location
    In the south
    Posts
    30
    Chiller only has so many seconds to make a certain amount of diffenential pressure or it faults out. If you are not controling the amount of water at start up to get the head pressure up to make the differential pressure it will fault. I live in the eastern part of Texas and have to use a control valve in order to keep this from happening. If it is needed this far south I am sure you need to do the same. I have also talked to the factory about this and my area is on the boarder line of needing to do this. Anywhere north of here it is amost required.

  13. #13
    Join Date
    Nov 2009
    Location
    Aptos, Ca
    Posts
    40
    Set up condensor pump to run for 5-10 minutes before starting chiller for good mixing, nobody likes a slug of cold water in the AM. If it has a condenser water regulating valve on the output of the condensor, make sure it is working properly. If it doesnt it needs one! Also be sure the differential pressure switch is adjusted correctly.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event