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  1. #1
    Join Date
    Dec 2005
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    UK
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    Gauge manifold question - High side gauge flickering?



    Hi guys,

    I've come across this many times before but have never really questioned it. What could it possibly mean when my high side gauge - when connected to a live system - is flickering between pressures. For example, rapidly flickering between 15 and 20 bar. I even tried using different gauges and hoses and it still flickered when connected to the discharge Schrader valve.

    Cheers

    Dan



  2. #2
    Join Date
    Aug 2001
    Location
    Gold Coast, Australia
    Posts
    601
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    22

    Re: Gauge manifold question - High side gauge flickering?

    It's just the refrigerant hammering. Worst on recips. usually. Obviously the flow from the discharge is not smooth, rather it's a series of pulses as the compressor discharge opens & closes.
    This is why many engineers opt for oil filled gauges.
    However, there are a couple of tricks to try with dry gauges:
    If your system has service valves, slowly close off the stem until the fluctuation goes. The gauge will still be open enough to the system to register 'true' changes.
    For schraeders, get a set of the tap type quick couplers & use the tap to close off the opening & stop the fluctuation. It also means you can recover your hoses into the suction when you're done.

  3. #3
    Join Date
    May 2012
    Location
    England
    Age
    53
    Posts
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    Re: Gauge manifold question - High side gauge flickering?

    .

    Sometimes it can indicate one of the valves is not seating
    properly on the valve plate and when the piston moves down,
    the gauge flickers because the pressure is passing the valve.

    The further away from the comp the less it happens and if
    you connect to the receiver it tends to not show at all.

    Regards

    Rob

    .
    .. ... -. .----. - / -- --- .-. ... . / -.-. --- -.. . / --. --- --- -..

  4. #4
    Join Date
    Aug 2001
    Location
    Gold Coast, Australia
    Posts
    601
    Rep Power
    22

    Re: Gauge manifold question - High side gauge flickering?

    Yep, true. Halfcan, if you suspect an issue with the valves, listen carefully for odd noises. Try a mechanic's stethoscope to listen to the pots & compare.

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