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  1. #1
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    frosting at expansion valve.



    hey lads. what can cause frosting around the expansion valve? its a ground source heat pump



  2. #2
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    Re: frosting at expansion valve.

    If you are talking about frosting round the valve and control motor, it is probably a refrigerant leak on the expansion valve, caused by the bellows cracking due to moisture and releasing refrigerant. Need to replace the expansion valve and motor, making sure to torque the motor to valve body to stop this happening again. Recover refrigerant and weigh quantity to known charge weight to prove refrigerant loss.
    Last edited by refcon32; 09-12-2011 at 10:23 PM. Reason: additional info

  3. #3
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    Re: frosting at expansion valve.

    Brian, we install a lot of GSHP. Frosting around the valve is because your system is running below 0C. What are your running pressures and temperatures? Frosting around the valve this time of the year and so early in the heating season is strange, unless to less coils were installed.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  4. #4
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    Re: frosting at expansion valve.

    @Refcon, why you think there's a motor? Where's the bellow on an EEV? Refrigerant loss can be found simply by verifying running pressures and temperatures without prior recovering. It perhaps was never charged correct the first time. I never depend on what others did before me.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  5. #5
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    Re: frosting at expansion valve.

    Without stating the obvious,could be that the system has just been turned on (cold water in the heating circuit)
    and the condensing pressure is just low, because of the water temp fact. The suction will follow.

  6. #6
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    Re: frosting at expansion valve.

    Quote Originally Posted by refcon32 View Post
    If you are talking about frosting round the valve and control motor, it is probably a refrigerant leak on the expansion valve, caused by the bellows cracking due to moisture and releasing refrigerant. Need to replace the expansion valve and motor, making sure to torque the motor to valve body to stop this happening again. Recover refrigerant and weigh quantity to known charge weight to prove refrigerant loss.
    Please expand on this as I cannot follow the logic at all..

  7. #7
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    Re: frosting at expansion valve.

    Thought the expansion valve was the type that has L shaped pipework and a drive motor sits on top to operate the valve by pushing the pin in and out of valve body to control fridge flow. As on airconditioning systems. Sorry for confusion
    Quote Originally Posted by r.bartlett View Post
    Please expand on this as I cannot follow the logic at all..

  8. #8
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    Re: frosting at expansion valve.

    Quote Originally Posted by mad fridgie View Post
    Without stating the obvious,could be that the system has just been turned on (cold water in the heating circuit)
    and the condensing pressure is just low, because of the water temp fact. The suction will follow.
    I wonder what type of pump control this heat-pump has? Interesting point MF.
    Engineering Specialist - Cuprobraze, Nocolok, CD Technology
    Rarefied Technologies ( SE Asia )

  9. #9
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    Re: frosting at expansion valve.

    Quote Originally Posted by r.bartlett View Post
    Please expand on this as I cannot follow the logic at all..
    Me neither Richard
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  10. #10
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    Re: frosting at expansion valve.

    Quote Originally Posted by refcon32 View Post
    Thought the expansion valve was the type that has L shaped pipework and a drive motor sits on top to operate the valve by pushing the pin in and out of valve body to control fridge flow. As on airconditioning systems. Sorry for confusion
    Ok but where are the bellows on a EEV
    (as Peter asked previously?)

  11. #11
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    Re: frosting at expansion valve.

    thanks for replies lads. just to elaborate on problem,the frosting is actually on the pipe coming from the expansion valve. i have recently done a short fgas course but am a complete novice. i have installed a lot of nibe pumps and never needed to know about the refrigeration side of them. this heat pump is a neura and the compressor is in a plastic container dropped into the lawn of a lads house. his controls are very industrial looking. when he switches on his heating the the controller registers a fault after a few minutes. when i went out to look at compressor, i noticed the frost on the pipe. the compressor can be heard running but no heat is produced.

  12. #12
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    Re: frosting at expansion valve.

    have u got gauges,what running pressures are u getting. what fault code
    Last edited by install monkey; 11-12-2011 at 09:56 PM.

  13. #13
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    Re: frosting at expansion valve.

    I thought F-Gas wasn't for complete novices..How nieve am I? :-/

  14. #14
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    Re: frosting at expansion valve.

    Brian

    if you're stuck i can give you a digout, pm me.

    alec
    Mostly found in the southern part of this green and pleasant land.

  15. #15
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    Re: frosting at expansion valve.

    The bellows are on main valve body where the output shaft of drive motor enter the valve.
    Quote Originally Posted by r.bartlett View Post
    Ok but where are the bellows on a EEV
    (as Peter asked previously?)

  16. #16
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    Re: frosting at expansion valve.

    A shaft seal then?
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  17. #17
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    Re: frosting at expansion valve.

    It sounds to me like the system haze a gas leak, phone a technician as u are going to break it if u do not have the experience to fix this simple problem. u will also then be sure that the system will function as designed.
    No comebacks.
    THE BEST WAY OF LEARNING IS TO DO IT YOURSELF!!!

  18. #18
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    Re: frosting at expansion valve.

    I should have a working diagram of the valve I am talking about. will look it out and put it on and all will be explained
    Quote Originally Posted by Peter_1 View Post
    A shaft seal then?
    Attached Images Attached Images
    Last edited by refcon32; 21-12-2011 at 08:53 PM. Reason: added diagram

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