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Adding brew and boiler pressure gauges to Expobar Office

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  • Adding brew and boiler pressure gauges to Expobar Office

    Hello folks,
    Well I have been the proud owner of my Expobar Office Semi-Auto for a month now and I have to say it was a bit of a learning curve from my old Cafe Roma. Only in the last week have I got my dosing and tamping down to the point where I am consistently achieving passable shots each time. Stretching the milk on this machine has also been a new experience but I am getting good results now with a good texture and nice sheen.

    I have just today checked the temperature inside the portafilter with a thermocouple over the lip and found that it held 94-92 degrees through the shot process even without a cooling flush, so pretty happy with that.

    I have been thinking of adding a boiler pressure gauge and brew pressure gauge on the front panel either side of the brew activation switch. There seems to be enough room there for a couple of smaller gauges. I am after a pair with a mounting size around 40-50mm. There seems to be a few available as a spare part on other machines that would fit the bill.


    I have had the covers off and had a look around but I am unsure where would be the best place to tap into to get a pressure reading.

    It seems to me that for the boiler pressure I could tap into the line for the steam wand just before it gets to the tap with a 1/4"x1/8" tee.

    For the pump pressure, do I have to take it from the top large pipe going to the top of the group head?

    Pic shows what I mean with the last two ideas:
    Click image for larger version

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    Question is, or can I use a 6mm push-in type tee fitting in the teflon line from the pump outlet to the tee for the boiler inlet, this would be cold water, so I imagine I could get away with polyethylene tubing up to my gauge instead of copper.
    Click image for larger version

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    The following is a schematic of the water circuit on this machine if someone who knows could fill me in with the best place to tap into.
    Click image for larger version

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    Any advice welcome. Thanks.

  • #2
    You can get gauges that have both brew and boiler pressure in one unit, have a look at the coffee parts website.

    The boiler pressure gauge can take its reading from anywhere on the boiler, it doesnt have to be above the water level (the one on my machine isnt) but would be better above the water level as there is less chance of scale ever developing inside the gauge.

    The brew pressure should be on from the tube post pump as close as possible to the brew head, so you maximise accuracy, as less pressure loss through bends/fitting/tube etc compared to just after pump.

    Cheers

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