Washing Machine Water Valve - How Fill Valves Work

Typical Washer Water Inlet Valve

How Does a Washer Fill Valve Work

A washing machine fill valve is an electromechanical device that is used to control the water that enters a washing machine. All washing machine fill valves work the same. Washing machine fill valves use a coil of wire encased in plastic, to create an electromagnetic field, lifting up a gate that allows water to enter the machine. These gates are held closed by the house water pressure. This is why sometimes when people come back from vacation they find that their washing machine has flooded their laundry room. In an effort to protect themselves and prevent water damage, they turned the main water supply valve off to the house. In some cases the main water supply valve because of corrosion or sediment, does not seat properly. When this happens, a small amount of water will continue to leak past the corroded valve. This water pressure is not sufficient to keep the water valve on the washing machine held closed. So when that happens, the gate on the washing machine fill valve opens up slightly, and water slowly runs in the machine. Given enough time, it would eventually flood the whole house.

The coils on a washing machine fill valve must have resistance to the flow of electricity, otherwise they would be a conductor just like a wire. Therefore you can use an ohmmeter to check for resistance to see if the coil is open electrically or not. When trying to determine what type of resistance you should encounter, ask yourself how much work this particular load is doing. For example, a fill valve is not doing very much work to open the gate and let the water flow, when compared to the motor on the washer. Therefore the fill valve will have a much higher resistance than the motor. If you have a washing machine that will fill with hot water, but will not fill with cold water, that is easy to diagnose. Assuming that both water valves are turned on behind the washer, and that the screens on the hoses are not restricted, all you need to do is reverse the connections on the fill valve. Set the timer on the washer to fill with hot water, and now if cold water enters the machine, then you know that the coil on the hot side of the valve is defective.