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Isomac La Mondiale OPV adjustment question

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  • Isomac La Mondiale OPV adjustment question

    Hello coffee snobs!

    I've recently bought a second hand La Mondiale which unfortunately wasn't well maintained but bit by bit I'm getting her sorted out. The boiler pressure gauge shoots up to about 14 bar when pulling a shot. I've found this statement elsewhere:

    "A professional grade dual-purpose pressure gauge allows you to accurately assess boiler pressure and pump pressure and an over pressure relief valve internally allows user regulation of pump pressure."

    Can anyone tell me how to adjust this?



  • #2
    Hey mate,

    Are you talking about the gauge on the bottom? If so this is the brew pressure gauge not the boiler pressure. This can be adjusted as you said by winding out the spring tension on the OPV.

    I have attached an exploded view of the Mondiale. The OPV is item 46. It sits just below/behind the boiler. You need to wind counterclockwise the part that the flexible drain hose attaches to. It might take you a few goes to get it right. I aim to set mine for about 10BAR on the gauge.

    Make sure everything is turned off and unplugged before you open her up.

    If you do need to adjust the boiler pressure this is much easier and can be done without pulling anything apart. Just remove the cup holder tray. The boiler pressurestat sits at the top of the machine on the right hand side (hot water tap side). It is black plastic and can be adjusted using a flat head screwdriver. Use a torch to look through the holes on top and you should be able to see it!

    Hope this helps,
    Attached Files


    • #3
      Thanks for the advice Craig. I'm successfully at about 9.5 bar now and yes it was the brew pressure, my mistake. The OPV wouldn't budge so I removed it and soaked it in descaler for half an hour which did the trick. Pulling some very nice shots now! :-)


      • #4
        Good to hear it's all working well. They are an awesome machine.

        I did find however that once it's been on for a while it would need a long cooling flush. If you experience the same you can fit a thermosyphon restrictor. I made one out of brass and fitted it to the top pipe entering the group. I settled on a 3mm orifice. Now my machine needs almost no cooling flush at all.

        I agree that they make very nice shots!!

        Attached Files


        • #5
          Originally posted by cdcdcd View Post
          Good to hear it's all working well. They are an awesome machine. I agree that they make very nice shots!!Craig.
          +1 to that!! If I could afford to collect machines, I would have kept one of the two I owned.