MotionRebuild shelfTest and identify

Solenoid water valve

Also called inlet valve, washer valve, ice maker valve.

A pilot-operated valve: a small coil opens a diaphragm and line pressure does the real work. Many need a minimum pressure to open fully. The coil voltage is printed and is often mains.

If you are new to this category

These parts spin, push, or pump. A motor is a machine that turns electricity into turning. Some start turning as soon as you connect a battery. Others look identical and will not move until a small circuit tells them which coil to power next. The label, or the number of wires, is how you tell them apart.

Count the thick wires before you apply power. Two wires usually mean a brushed motor that can run from a battery. Three thick wires usually mean a brushless motor. Keep the board that came with a brushless motor.

A brushed motor

Two wires mean you can try a low, current-limited voltage and it should spin. The case often hides a label. If the only label you can find is on the machine, that voltage is the one to believe, not a hobby guess.

Mains voltage. Line voltage, and the DC bus just after the rectifier, both kill. A disconnected cord is not a discharged supply.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
Coil	120 VAC, 230 VAC, or 12/24 VDC. The body is usually marked.
Ports	Garden-hose or push-fit. Washer valves are often dual (hot and cold).
Fail	Stuck diaphragm or a cracked screen, more often than an open coil

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

Irrigation
Rain barrels
Any low-pressure water job that can live with mains or a proper DC coil

Leave this one when

You only have a 5 V GPIO. This is not a hobby servo. Also skip if the diaphragm is torn; the coil being fine does not make it a valve.

Buying a new one is the better idea when

A 12 V irrigation valve with a known pressure range, if this one is mains and your system is not.

How to tell if this one still works

Coil resistance is hundreds of ohms on mains valves, tens on 12 V. Then water and rated voltage. No voltage experiments on a flooded bench.

Tools you will want: Meter, Bucket.

Words on this page

Short meanings, so the rest of the entry is readable if you are not already doing this every weekend.

mains: Ordinary household wall power. It can kill. Unplug before you open anything that used it, and do not experiment on live wiring.
diaphragm: A flexible disc that moves with pressure or with a pump. In a washer it is how a small switch senses water level without the switch getting wet.
GPIO: A logic pin on a small computer board, such as an Arduino or a Pi. It can light an LED. It cannot run a motor or a heater by itself.

Where people actually find it

2 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Washing machine	Prize	1	usually	Where the hoses enter.
Dishwasher	Prize	1	usually	Inlet.

Prize — take this firstWashing machine1 · usually
In this particular machine
Dual solenoid, mains coil or sometimes 12 VDC. The body is marked.
Where to look
Where the hoses enter.
How to get it out
Shut the house water off first.
The condition to expect
Screens clog. Coils usually survive.
Prize — take this firstDishwasher1 · usually
In this particular machine
Solenoid, usually mains.
Where to look
Inlet.
How to get it out
Read the coil.
The condition to expect
Screens clogged, coil fine.