オリジナル投稿者： Mr Oddjob ,
The pressure switch indicated by Mayer can be tested by disconnecting the tube from the tub and gently blowing into it. As the pressure builds a faint click should be heard from the switch unit ,indicating that the switch contacts have been activated. Another faint click will be heard only when you release the pressure. If the switch clicks before you release the pressure, then the diaphragm inside the unit is faulty. Another cause could be a faulty solenoid coil on one of the inlet valves. There are usually two, (hot and cold). Isolate the power from the machine and disconnect the two wires from one of the solenoids. With a multimeter set on a low OHM's range, place the prods one on each terminal of the solenoid. If a reading is obtained, the coil is good. If no reading shows, then the coil is open circuit and a new solenoid valve is required. Hope this is helpful.