Check the return pipe to the tank coming from the expansion valve, lift this tube out of the tank and observe, is water coming out. It should be as, when the switch isn’t lifted to make a shot, the pressure is going direct to the sealed brew circuit and the expansion valve will open so this is maintained at 9 bar.
Just to elaborate on this
MediumRoastSteam How do you know the fill sensor is working? If you disconnect it, what happens? Does the pump still run?
If you disconnect the fill sensor, the pump will definitely run.,,,A quick test can be to disconnect the fill sensor wire and touch it to the boiler or the frame of the machine. A more thorough check is to disconnect the thin black Gicar earthing wire (which should be to the frame not the boiler) and the fill probe wire, then connecting them together…should stop the pump.
If it doesn’t, then I can only suspect the Gicar box itself is faulty (or there is a break in the wires, which you can check with a resistance meter) and unfortunately, it’s not such a cheap item! You actually do need that exact box from ACS as it contains custom programming specific to that machine.
One key point to make is that if the level in the service boiler is low and the autofill solenoid has failed (or bad connection)…the service boiler will never fill and the machine will constantly call for water…the test above will confirm this if connecting the wires immediately stops the pump.
