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Thread: Steam pressure drops rapidly

  1. #1
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    Steam pressure drops rapidly

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Ive adjusted my pressure switch so it cuts out at 0.9bar. It cuts in at 0.6bar. After turning the machine on I wait about 1/2hr for it to warm up. By this time the pressure switch has cycled at leat 2 times. I then open the steam valve and the pressure quickly drops to near 0bar. Only after a few more cycles does it produce good dry steam at between 0.6 and 0.8 bar.

    Whats going on here? It doesnt seem right. I have re-seated the taps and the OPV recently, maybe Ive missed something? I adjust the OVP to about 1.6bar, this should be OK yeah?

  2. #2
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    Re: Steam pressure drops rapidly

    From your decsription your anti-vacuum valve is stuck closed and you are experiencing the "false pressure" indication that results from having a stuck closed anti vacuum valve, & where the operator is not following the practice of bleeding all the pressure out of the boiler upon switching off by opening (and leaving open) one of the steam taps, and making sure the tap is still open when switching the machine back on...until it starts to leak steam from the end of the steam pipe....before closing the tap.

    The fix is to:

    a) tap the nipple on the anti vacuum valve with the end of a screwdriver to unstick it and

    b) always follow the practice noted above, of bleeding off all pressure when switching off and back on etc etc etc.

    The OPV on the boiler has nothing to do with this, its just a safety valve that *blows off at a pressure way above normal working pressure.

    c) If you are tapping the anti vacuum valve while the machine is pressurised, make sure you dont burn yourself

    d) before lifting the lid on any esp machine dont just switch off, UNPLUG it from the wall....dont take any chances with elektrickery.

    Hope this helps.

    Regards,
    Attiklio
    aka FC, first / original CS site sponsor. *

  3. #3
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    Re: Steam pressure drops rapidly

    Where is this anti vacuum valve normally located? Thanks for the normal switch on and off procedure, Ive certainly NOT been following that.

  4. #4
    Senior Member Dennis's Avatar
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    Re: Steam pressure drops rapidly

    Attached to the boiler - and looks just like this...


  5. #5
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    Re: Steam pressure drops rapidly

    Here are piccies of 2 different variations on the Anti Vacuum valve, one of which is in an old Bo-Ema, the other is a newie being held in the hand of my beautiful young assistant!

    Regardz,
    Attilio
    aka FC, first / original CS site sponsor


  6. #6
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    Re: Steam pressure drops rapidly

    ditto


  7. #7
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    Re: Steam pressure drops rapidly

    Thanks guys. My machine does not have one of those.
    I have adopted Attilios recomendations and this works a treat. Just have to remember to close the steam valve.



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