A bad connection, either a poor and loose connection could cause several problems. First of all the pump could overheat a bit and not be able to go to full pressure. The connection itself could overheat and cause a lower voltage to reach the pump but cause higher amps through to the pump. I think you have found the main problem. Good trace on all the components and fittings.
It has more to do with the grind size, without the resistance from finer grinds you won’t see close the the maximum pressure set at the OPV. The gauge in that design shows a good indication of actual pressure at the puck, which is a useful thing.
Nice. Also explains why the volumetric measurement is dodgy when the OPV bypasses some flow - it's a low pressure flow meter and has to be on the suction side of the pump, so only sees total flow. They'd need a more expensive (and potentially less reliable) high pressure flow meter device on the downstream side of the OPV for accurate measurement under all conditions.
Another excellent video. I think if with blind basket there is full pressure, then the machine is ok. I bet is too coarse grinder. I love to se any machine internals . Thanks for sharing.
Could you please tell me how to remove the filter screen, which was omitted at the beginning of the video. I would like to remove it for cleaning, but it is too hard to move.
Do you mean the shower screen? I used a flat screwdriver to pry it out (work around it slowly so it doesn't bend). Just make sure you don't stab a hole in the rubber gasket, but it's not that fragile.
