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Thread: Pump pressure manomenter

  1. #1
    Senior Member
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    Pump pressure manomenter

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    The pump pressure manometer in a machine without an OPV but with a vibrating pump gives an indication about how much you've overdosed or grinded too finely. But if you put on an OPV, you can't see how much any longer, you only see it maxed at 9 bar (or whatever the OPV is set at).

    Wouldn't it be ideal to put the manometer before the OPV, to give proper indication of overdosing? Also, I assume this would be tricky with a rotary pump, as the OPV is sort of integrated?

  2. #2
    Senior Member level3ninja's Avatar
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    The OPV relieves the pressure in the whole system by draining excess water, it is not like a pressure limiting device where the pressure is high on one side and low on the other. There will be a pressure difference between the pump, the puck, and the OPV, but it will only be the total of the pressure loss along the pathway. Regardless of this, you don't want your pressure too high, the coffee will be terrible once you're too far past the OPV set point anyway. Rather than using the pressure to estimate exactly how far overdosed or too fine your puck is, you can know that if your pressure gauge is showing the OPV set point you've created too much resistance and need to back the dose or grind off.
    Last edited by level3ninja; 4th January 2019 at 10:25 AM.
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  3. #3
    Senior Member artman's Avatar
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    Behmor Brazen - $249 - Free Freight
    As above and also the extraction flow rate also indicates if you have over dosed.

    Cheers
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