Results 1 to 11 of 11
  1. #1
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191

    CVHE purge issues

    I have 2 CVHE side by side in parallel, they have isolation valves on chilled water,that open when chiller is on. On the one chiller the isolation valve don't hold and when the chiller is off, chilled water gets circulated through the barrel. This machine keeps getting air in it, Another mechanic leak checked the machine and said the reason it is getting air in it, is due to chilled water being circulated through the bundle in off cycle and pulling air in through purge. First is this possible and if so how?

  2. #2
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,110
    What kind of purge is on the chiller , Purifier or Earthwise . Has anyone ever changed the solenoids on the purge . If its a purifier the big mistake is to install the solenoids with the flow arrows pointing in the direction of flow on both solenoids . This is incorrect they should oppose each other .
    Try valving the purge off and see if it sucks air , if it doesnt then pressurize the purge with nitrogen and fix the leaks . They should not suck air in they should hold both pressure and vacuum .
    The toy chest is officially full ... I got a new toy..... 2007 Aston Martin V8 Vantage
    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 .

  3. #3
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191
    Quote Originally Posted by Healey Nut View Post
    What kind of purge is on the chiller , Purifier or Earthwise . Has anyone ever changed the solenoids on the purge . If its a purifier the big mistake is to install the solenoids with the flow arrows pointing in the direction of flow on both solenoids . This is incorrect they should oppose each other .
    Try valving the purge off and see if it sucks air , if it doesnt then pressurize the purge with nitrogen and fix the leaks . They should not suck air in they should hold both pressure and vacuum .
    It's a purifier( I believe), I haven't seen this job yet but will be there tomorrow. And I will check the above. So what your telling me is that sucking air in via purge because chilled water isolation valve is bad and letting chilled water pass in off cycle is not normal correct? Our senior chiller mechanic is who told me this, I've been working under him learning chiller's for the last 3 years. When he told me this it made no sense to me and when I questioned it, he sounded like a politician and I could not get a straight answer.

  4. #4
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,110
    Quote Originally Posted by fr420 View Post
    It's a purifier( I believe), I haven't seen this job yet but will be there tomorrow. And I will check the above. So what your telling me is that sucking air in via purge because chilled water isolation valve is bad and letting chilled water pass in off cycle is not normal correct? Our senior chiller mechanic is who told me this, I've been working under him learning chiller's for the last 3 years. When he told me this it made no sense to me and when I questioned it, he sounded like a politician and I could not get a straight answer.

    They should not suck air in they should hold both pressure and vacuum .
    Chiller off chiller on, flow no flow makes no difference if its suckin air its got a leak period .
    Sounds to me like you have a high side leak on that machine , it sucks air in because the whole chiller is in a vacuum no just the evap when its idle .
    Go over the chiller with a set of wrenches and check ALL the flat gasket joints for torque .
    The toy chest is officially full ... I got a new toy..... 2007 Aston Martin V8 Vantage
    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 .

  5. #5
    Join Date
    Aug 2000
    Location
    Phila, PA
    Posts
    191
    Ok thanks, That's what I thought but this guy has more experience then me on low pressure machines and just wanted to make sure I wasn't missing something.

  6. #6
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,524
    Quote Originally Posted by fr420 View Post
    Ok thanks, That's what I thought but this guy has more experience then me on low pressure machines and just wanted to make sure I wasn't missing something.
    age does not equal intelligence.

    lots of years in the trade does not equal 'smarts' either.
    "If you pull one more stunt like you just pulled with Tommy, you won't have to get on a plane because I will personally kick your ass from here to Korea!" - Best of the Best

  7. #7
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,132
    Reminds me of something I heard long ago: "There's a difference between 10 years of experience, and 1 year of experience repeated 10 times".

  8. #8
    Join Date
    Aug 2009
    Location
    Jurupa Valley, CA
    Posts
    1,787
    No, chillers should not leak - that said, no system is perfect, so the fact that the chilled water continues to flow through the evaporator keeps them at a vacuum, exasperating any potential leaks that may be there. We have 5 CVHE's of various age, and they all have "pre-vac" heaters on them to keep the system neutral when offline - of course, if the chilled water is flowing, the heaters aren't going to keep up with them, and it will be sitting at a vacuum. Is the chilled water flow the cause of your leak? no, but if it wasn't flowing, you would not be leaking near as much (I think the zero point of R-11 is about 75F or so, so if it wasn't flowing, and the water came up to room ambient, the leakage would effectively stop).

  9. #9
    Join Date
    Oct 2010
    Posts
    121
    Link gone

  10. #10
    Join Date
    Oct 2010
    Posts
    28
    They should not suck air in they should hold both pressure and vacuum .
    Chiller off chiller on, flow no flow makes no difference if its suckin air its got a leak period

    isolate the purge from the chiller,and leak check the purge with nitro, not only the solenoids will leak, also the float switch that is located on the bottom of the cannister,and go up in pressure when you are leak checking the purge with nitro,

  11. #11
    Join Date
    Jul 2013
    Location
    N.H.
    Posts
    35
    Leaking though the purge should be eliminated if the purge was installed with an isolation valve. The chiller probably is leaking. Check your purge rates. If you have excessive purge rates you should leak check the whole chiller. The discharge veloute is a usual suspect.Use hot water to bring the pressure up to 8 lbs but never higher than 10 or you may rupture the relief. The relief if set to fail at 15 psig.

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