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  1. #1

    Hmm Expansion Valve mushrooms

    Hello Techs,

    Have a refrigeration loop that cools water/methonal to help bring testing room temp to operating conditions.

    We are working with 507R and have adjusted this to around 10 PSI superheat.
    This EV is ahead of a DX coil with a solenoid valve in front of it.
    Feeler bulb is on suction line after evap with a stepper valve after it. Inlet pressure is about 180 to 190 PSI. suction around 110-120 PSI.

    Problem....the top on my expansion valve is mushrooming after a few months of operation. Just changed it out! Looking for a solution to keep the pressure from damageing the valve during off cycle or start up.

    Any thoughts.....

  2. #2
    Join Date
    Apr 2012
    Location
    Paper Street Soap Company
    Posts
    2,304
    The power head is inflating to the point where its no longer operational ?

    The power head is essentially a diaphragm with R507 trapped inside as a sensing reference.

    Is the bulb insulated ? Is it exposed to excessive ambient on the off cycle ?

  3. #3
    Join Date
    Apr 2011
    Location
    SE Washington
    Posts
    537
    is a balance port txv available?
    Total Energy Management, inc

  4. #4
    Hey Guys,

    This valve is in a cabinet along with compressor and the temp can reach 90+ in off cycle. Not necessary to be insulated as its opeperating temp is with 180 to 190 discharge pressure. Do have an equallizing line between suction and supply. I think this electronic stepping valve may close on the off cycle....checking into that....
    I replaced this valve two months ago as it was not performing and was really mushroomed after 2 years of operation. Present is starting to mushroom.

  5. #5
    System gave me some trouble last week, but is operating OK now with 8 degree superheat. and hold temp rock steady. I just know that I will need to replace again, and want a perminet fix this next time.

    Thanks for looking....

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,125
    Inlet pressure is about 180 to 190 PSI. suction around 110-120 PSI?

    10 PSI SH?
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,125
    Moved to Tech to Tech.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  8. #8
    Hey Guys,
    Just an update on the problem I had with the expansion valve being dis-formed.
    Turned out this was happening on the off cycle. Stepper valve after the dx-coil was closing at times locking the refrigerant in this loop. Pressure would climb upward to 300 psi and this pushing against the diaphragm.
    Fix....put a n/o solenoid over the stepper valve to prevent pressure from building.
    Braveheart....

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