Page 1 of 2 12 LastLast
Results 1 to 13 of 21
  1. #1
    Join Date
    Mar 2013
    Location
    Central IL
    Posts
    103

    Confused high head lock out

    Have a Leibert unit that is continuiously locking out on high head pressure. Haved ohmed out high press switch and guaged pressures, all ok while unit in opperation, then usually with in 3-4 days unit locks out on high head press. Condenser is on the roof and has been 15-30 degrees out side temp. Cooling a control room for University tv station. Any Ideas?

  2. #2
    Join Date
    Mar 2010
    Location
    Morgan Hill Ca.
    Posts
    1,219
    Yep, quite a few actually..

    Likely the issue is related to refrigerant charge or the condenser fan controls.
    If a day goes by and you have learned nothing, I hope you got a lot of sleep.

  3. #3
    Join Date
    Mar 2013
    Location
    Central IL
    Posts
    103
    Replaced condenser fan about a month ago, and pressures look good. Was going to remove TEV from Evap to see if it may be causing me problems. The unit runs 3-4 days no problem, then I get called due to it being locked out on high head.

  4. #4
    Join Date
    Mar 2010
    Location
    Morgan Hill Ca.
    Posts
    1,219
    Quote Originally Posted by Abrnth3 View Post
    Replaced condenser fan about a month ago, and pressures look good. Was going to remove TEV from Evap to see if it may be causing me problems. The unit runs 3-4 days no problem, then I get called due to it being locked out on high head.
    How many condenser fans are there and are any of them on a P66?

    You have to remember that typically the hps is on the discharge of the compressor. Not the liquid line.

    I would check the refrigerant charge and the condenser again.

    Good hunting.

    GT

  5. #5
    Join Date
    Mar 2013
    Location
    Central IL
    Posts
    103
    1 condenser fan. P66, is this a cold wheather kit ? HPS is on the discharge of compressor. Will check charge again but, pressures were good when I reset Unit and thought they would of been the highest when Unit was trying to cool the room down at start up.

  6. #6
    Join Date
    Aug 2010
    Location
    Northern Cali
    Posts
    72
    Does the cfm have a capacitor ? Did you replace it when you replaced the motor? And what about the Condenser coil (Clean/dirty)? I know these are basic questions.....

  7. #7
    Join Date
    Nov 2001
    Location
    Seattle, WA
    Posts
    7,744
    Pull the charge and recharge according to factory specs.
    "The American Republic will endure until the day Congress discovers it can bribe the public with the public's own money.
    - Alexis de Toqueville, 1835

  8. #8
    Join Date
    Dec 2012
    Location
    Dodge City Kansas
    Posts
    13
    the P66 is an Electronic Fan Speed Control and is only to be used with single phase motors and intended for use with solid state motor controls.

    Is that the motor type you installed?

  9. #9
    Join Date
    Dec 2012
    Location
    Dodge City Kansas
    Posts
    13
    the P66 is an Electronic Fan Speed Control and is only to be used with single phase motors and intended for use with solid state motor controls.

    Is that the motor type you installed?

    Johnson Control's .pdf is here http://cgproducts.johnsoncontrols.co...2476641482.pdf

    Sounds like this is a likely culprit.

    Russ

  10. #10
    Join Date
    Jul 2012
    Location
    Western KY
    Posts
    1,221
    Are all fans coming on? Amp them out may have one laying down after some run time. Check the bearings as well, if you have one getting tight it will heat the motor up. Also check all fan controls. Verify they make and break where they should. I would eliminate all things cond air flow before any thing else.

  11. #11
    Join Date
    Mar 2010
    Location
    Morgan Hill Ca.
    Posts
    1,219
    Of you only have one fan motor then this is probably a fairly small unit. Model numbers are always helpful in these cases.

    You have to keep on mind that a low charge condition can trip the discharge pressure switch also.

    Keep us posted. The resolutions are more helpful to other people who read these.

  12. #12
    Join Date
    Mar 2013
    Location
    Central IL
    Posts
    103
    Thanks to all for the imput, I will look into this ferther and let you know what I find.

  13. #13
    Join Date
    Nov 2008
    Location
    Long Island NY
    Posts
    179
    Does that new motor have sleeve bearings or ball bearings?

    Sent from my SGH-I777

Page 1 of 2 12 LastLast

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