When a washing machine is set to run a wash cycle, the user sets the appropriate temperature for the type of clothing being washed. The water that comes into the washing machine is controlled by the washing machine solenoid. This mechanism reacts to user-controlled settings, allowing the appropriate amount of hot and cold water to enter the machine during a cycle.
During installation, a washing machine is connected to both the cold and hot water lines. Once the machine is in place the taps for these water lines are opened and left on to allow for normal operation. Each line connects to the inlet side of a valve assembly that includes the washing machine solenoid. The valve assembly has one output, which feeds water into the tub if the washing machine.
When the washer is turned off, the valves are closed and no water enters the tub. When the wash cycle calls for cold water, the solenoid opens the cold valve, and cold water flows from the inlet hose into the washer. If the wash cycle calls for hot water, the solenoid opens the hot valve instead, and hot water flows from the inlet pipe into the washer. When the cycle calls for warm, the washing machine solenoid opens both valves, and a mixture of hot and cold enters the tub simultaneously.
The washing machine solenoid is operated by an electrical signal from the machine. This signal is sent by the machine in response to events in its programming that indicate it is time to add water. After the solenoid receives the message to open a valve, it gives the appropriate valve a physical push that causes it to open. When it is time for the valve to close, the solenoid pulls it shut again.
Sometimes a washing machine will not send the proper temperature water into the tub, or it won’t send any at all. This can be an indicator of several possible issues. The simplest possibility is that the water is turned off at the tap. If both taps are turned on but the water is still not flowing properly, the problem is most likely the washing machine solenoid. One or both of the valves may not be opening when it should or is remaining open when it should be closed, indicating a likelihood that the solenoid needs to be replaced.
What Does a Solenoid Do in a Washing Machine?
A solenoid is simply a switch. It makes something turn on or turn off. In the case of the washing machine, the solenoids are positioned to switch on the normally closed flow of water from one of the two water inlets (hot and cold). A very small, low amperage control voltage is used to energize electromagnetic coils in the solenoid. The electromagnets pull a metal piece out of the way, acting as an opening valve to allow water flow in the washing machine.
A spring is sometimes used to keep the valve normally shut and only when a solenoid is energized does the valve move to overcome the spring. With some other machines, instead of using a spring to keep the valve in a normally closed position, the water pressure itself is routed to push against a lever which forms a tight seal to shut off the flow of water. This is similar to how a toilet float valve works.
How To Test a Washing Machine Solenoid
The steps the machine takes to power solenoids on or off must be understood before attempting to troubleshoot the system. Some type of voltmeter, multimeter, or test light will be needed to alert voltage using a set of probes. If there is no voltmeter available, an operator can just listen and feel closely for an audible "click" sound that is common to all solenoids. Some solenoids are louder than others.
Washing machines have different amounts of solenoids depending on the model. All washing machines have two main solenoids that control the inlet water. Other solenoids could be inside the machine that could be used to operate motors and pumps.
To test a solenoid, the operator must have access to the electric terminals on the outside of the solenoid. These are located at the spot where the water inlets from the hose connect to the washing machine.
Washing Machine Main Solenoids (2) Operation
- User inputs desired settings for each wash and presses START.
- The machine's brain sends a signal to one or both of the TWO water inlet solenoids. HOT, COLD, or WARM (both) are possible settings the machine can choose.
- Machine's solenoids remain energized for the duration required to fill the desired water to the desired water level.
- Once the desired water level is reached, the machine sends a signal to de-energize the solenoid. This sends the valve back to its normally shut position.
Washing Machine Main Solenoids Integrity Test
- Choose one of the main solenoids. Locate the terminals where the machine's brain connects via wires to the solenoid.
- Without disconnecting anything, place the meter probes - one on each terminal.
- Command the solenoid "on" by setting the machine to a setting that will send a signal to the solenoid being tested.
- The meter should indicate no voltage when off, and should indicate operating voltage in addition to an audible "CLICK" sound coming from the energized solenoid once the cycle starts.
- If the machine doesn't send a signal, the meter will remain at near-zero voltage and there will be no sound coming from the solenoid. The valve should remain shut.
- If the signal is indicated by the meter and there is also a click sound from the solenoid, yet the water still doesn't flow, there may be an issue with the water pressure at the inlet or there may be a broken valve mechanism that the solenoid is coupled to.
- If the signal voltage is indicated, but the solenoid doesn't click and the water doesn't flow, replace the solenoid.
- A solenoid that clicks usually means that it is working properly. If the operator can mimic the control voltage, he or she can test the solenoids with the machine unplugged and the terminals disconnected. Place the wires that will send control voltage to the solenoid's terminals while feeling for and listening for the click.
- If the solenoid doesn't click or perform its function when energized with proper control voltage, it must be replaced. Manufacturers do not usually recommend rebuilding or repairing broken solenoids.
Washing Machine Solenoid Valve Repair
Doing the research and buying the parts for a DIY repair could save a bundle for those of us who aren't afraid to turn a wrench. The parts might be difficult to obtain promptly, so be sure to plan ahead. It may not be necessary to replace a broken solenoid with the exact same part. A suitable solenoid that works on the same voltage and fits in the same spot should work out.
Sometimes people will advertise on Craigslist or Facebook Marketplace that they buy broken washing machines or they are selling some machines they have recently fixed. If the machine can easily be transported, maybe it can be brought to someone to be fixed and picked up later.