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Thread: LLSV

  1. #1
    Join Date
    Jul 2011
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    Columbus, Ohio
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    LLSV

    Is there a maximum pressure differencial of a LLSV. Application runs 275 head 60 suction and the stinking solnoid valve sticks open unless the delta P is lower at around 225 head, 60 suction. Brand new alco/emmerson 7/8 LLSV. Swapped the internal diaphram and head assembly out from another new valve, same thing. Wanted to make some calls but did not have time, thought I would try here. Thanks.

  2. #2
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    Quote Originally Posted by synergy View Post
    Is there a maximum pressure differencial of a LLSV. Application runs 275 head 60 suction and the stinking solnoid valve sticks open unless the delta P is lower at around 225 head, 60 suction. Brand new alco/emmerson 7/8 LLSV. Swapped the internal diaphram and head assembly out from another new valve, same thing. Wanted to make some calls but did not have time, thought I would try here. Thanks.
    This is just from memory, but I thought all refrigerant SV had a MOPD of 300psi.

    You have any more info? Maybe it's not the LLSV, that's leaking buy.

  3. #3
    Join Date
    Mar 2003
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    7,321
    Thee is a problem with some late model valves, whereby the valve sticks slighlty open when deenergized. The fix is a bras washer installed between the actuator and valve body.

  4. #4
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    Jul 2011
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    Columbus, Ohio
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    more info

    Water to water heat pump chiller, one of a kind I think, runs head pressure of 275Psig for hot water to the A/H of 105 degrees. Compressor had failed,after replacing I found the LLSV would at times not close and the compressor would have run until it either burned up or went off on high head pressure. Can pull the coil right off the valve and it stays open, pressures dont even blink, keeps right on running. If you cycle the unit control relay befour it gets to a head above 230psig it will pump down as intended. It holds tight and does not leak by at that point. Go figuer.

  5. #5
    Join Date
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    Northern VA
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    Sporlan has a designated inlet and outlet.I believe ALCO does too.
    Did a leaking solenoid cause the previous compressor to fail?
    "Iron sharpeneth iron..."

  6. #6
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    Nov 2011
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    What would happen if the LLSV was installed backwards?

  7. #7
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    Jul 2011
    Location
    Columbus, Ohio
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    In the right direction

    The arrow on the valve is pointed to the TXV, it is in the right way. Don't know what caused the original failure, but this problem is on my short list. It is like 200 PSI Diff is the maximum it can close against, but that seems like a normal application demand of a LLSV. Maybe a flow thing? To much liquid velocity? 15 ton compressor, 27 Lb charge, R-22, through a 7/8 liquid line. It all seems like the right fit, but two valves doing the same thing at the same point, makes one wonder.

  8. #8
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    Location
    Columbus, Ohio
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    Hmm In the right direction

    The arrow on the valve is pointed to the TXV, it is in the right way. Don't know what caused the original failure, but this problem is on my short list. It is like 200 PSI Diff is the maximum it can close against, but that seems like a normal application demand of a LLSV. Maybe a flow thing? To much liquid velocity? 15 ton compressor, 27 Lb charge, R-22, through a 7/8 liquid line. It all seems like the right fit, but two valves doing the same thing at the same point, makes one wonder.

  9. #9
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    Nov 2011
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    British Columbia
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    Doesn't make sense. Scrap the Alco and try a Sporlan to get you going again, then do forensic on the Alco. ?? Maybe a bleed port is blocked?

  10. #10
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    Dec 2003
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    Northern VA
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    Sounds good to me too.
    If the old compressor was acidic I can see the LLSV valve body being copper plated. If new guts were installed into the old valve body, I can see how the new parts would bind in the copper plated body, but as I read it, you have already replaced the valve body also.

    24- 27 volts at the valve coil?

    And best of luck.
    "Iron sharpeneth iron..."

  11. #11
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    Jul 2011
    Location
    Columbus, Ohio
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    Sporlan sounds good

    I may have to go the Sporlan route, pain in the butt to replace at this point, but don't know what else to do. The alco valve has a little round diaphram and a spring. Not to sure on how it works. The bleed port does not seem to leak when I try to blow through it and the little hole in the diaphram thingy is clear. The valve was installed new out of the box, alone with the TXV, sight glass, ect. The old compressor was grounded but not real dirty. Not to happy either with how the thing can just run wild, if the solnoid valve sticks. Thinking time delay or something to keep that senario out of the picture. Or, do I even need it to pump down, could I not just have the compressor shut off with the LLSV. Will check Monday to see if valve closes when compressor is turned off at same time. That would be the easy way out.

  12. #12
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    Sep 2008
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    Synergy,

    The Alco/Emerson solenoid valves are an internally piloted valve. There are actually 2 solenoid valves in one. A very small one right under the coil that operates the larger one that actually controls flow.

    If I were you and the 'rebuild' that you did had no effect, I would cut that valve out and burn in a new one. No questions asked.


    I'd use a Sporlan, too. Better valves, IMO.


    I would also perform a detailed post-mortem on the solenoid to attempt to determine a cause of failure.

  13. #13
    Join Date
    Jul 2011
    Location
    Columbus, Ohio
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    136

    Thanks

    Will replace, dissect, and report.

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