Penguin 45 offered this advice: “Presumably the inlet valve has failed – this is integral with the Aquastop hose and is therefore rather pricey. If you have a test meter, pick up the leads coming out of the sheathing and do a resistance test. You’re looking for approx 3.5kOhms when the circuit is split. ” I’ve done the test as suggested, and the reading is 1.95kOhms – what should I do next?