How Washer Fill Valves Work

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. A fill valve uses a coil of wire, encased in plastic, to create an electromagnetic field which lifts up a gate to allow water into 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. Homeowners in an effort to protect themselves and prevent water damage turn the main water supply valve off to the house before going on vacation. In some cases, the main water supply valve does not seat properly due to a build up of corrosion or sediment. If the valve is not properly seated, a small amount of water will continue to leak past the corroded valve. This water pressure is not sufficient to keep the water fill valve on the washing machine held closed. Ultimately, the gate on the washing machine fill valve opens up slightly allowing water to slowly run into the machine. Given enough time, it will eventually overfill the tub and 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 does little work to open the gate filling the washer with water as 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, here is the easy way to diagnose the problem. Make sure that both water valves are turned on behind the washer and that the screens on the hoses are not restricted. Next, all you need to do is reverse the hose connections on the fill valve. Set the temperature on the washer to fill with hot water, and now if cold water enters the machine, then you know that the coil on the cold valve was defective. Remember to reconnect the correct hoses to the new water valve.

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.