How to Test a Solenoid Valve with a Multimeter
When a solenoid valve stops working, the fault is usually one of two things: the electrical coil has failed, or the valve mechanism is stuck, blocked or worn. A multimeter and a few minutes of methodical checking will tell you which — and save you from ordering the wrong part. This guide walks maintenance engineers and OEM technicians through testing a solenoid valve step by step, from confirming the electrical supply to checking the coil and the valve body itself.
If you are trying to diagnose a specific symptom such as a valve that only opens slightly or a persistent leak, our solenoid valve fault diagnosis guide works through causes and fixes by symptom. This page focuses on the electrical and mechanical tests themselves.
Before you start: isolate and make safe
Solenoid valves combine mains or control voltages with pressurised media, so treat every test as live until proven otherwise. Electrically isolate the circuit before disconnecting any wiring, and lock off the supply where practical. Depressurise the pipework and, where the media is hot, aggressive or flammable, drain the line and allow it to cool. Never rely on the valve itself to hold back pressure while you work on it. Once the circuit is isolated and the line is safe, you can begin testing with confidence.
Step 1 — Check the supply voltage reaches the coil
A valve that will not operate is very often a supply problem rather than a faulty coil. Set your multimeter to the correct AC or DC voltage range and, with the circuit energised and the connector plugged in, measure across the two coil terminals (or the corresponding pins at the DIN 43650 connector). You should read the coil's rated voltage — for example close to 230V AC, 110V AC or 24V DC depending on the coil fitted.
If there is little or no voltage, the fault lies upstream in the wiring, control relay, PLC output or fuse — not in the valve. If the reading is significantly low, check for undersized cabling, a failing transformer or a poor connection. Confirm the coil marking matches your supply; a full explanation of common ratings is on our solenoid valve coil voltage guide. Only once you have confirmed the correct voltage is actually arriving at the coil is it worth testing the coil itself.
Step 2 — Test the coil for continuity and resistance
This is the single most useful test. Isolate the supply, unplug the connector and set your multimeter to resistance (Ω) or continuity. Measure across the two coil terminals. What you are looking for is a sensible, finite resistance reading. The exact figure depends on the coil's voltage and wattage, so compare it against the manufacturer's stated coil resistance where available.
The three outcomes to recognise are:
| Multimeter reading | Likely condition | Action |
|---|---|---|
| A stable, finite resistance | Coil winding is intact | Coil is probably good — investigate the valve body |
| Open circuit (OL / infinity) | Winding is burnt out or broken | Replace the coil |
| Near-zero / very low | Shorted turns within the winding | Replace the coil |
An open-circuit or shorted reading confirms a failed coil. A healthy reading means the electrical path is intact and the fault is more likely mechanical. As a rough guide for a DC coil, the expected resistance is approximately the voltage squared divided by the coil wattage — so a 24V DC, 8W coil sits in the region of 70 ohms — but always check the specific figure for your coil rather than assuming.
A note on AC coils
AC coils catch people out. A multimeter measures only the direct-current resistance of the copper winding, which for an AC coil is often just a few ohms to a few tens of ohms — far lower than you might expect from its power rating. That is normal: in service the coil's opposition to current is dominated by inductive reactance, which a standard meter does not read. So for an AC coil, a low resistance is fine; what matters is that it is neither open circuit nor a dead short. This is also why an AC coil left energised while its armature is jammed open can draw excessive current and overheat — the reason some valves buzz or run hot, as explained on our pages about why solenoid valves buzz and why coils get hot.
Step 3 — Test the coil off the valve (the "click" test)
If the coil reads healthy but the valve is not shifting, remove the coil from the armature tube and hold it (safely insulated) while an assistant briefly energises the circuit. A good direct-acting coil will produce a distinct magnetic pull you can feel on a screwdriver or the armature, and you should hear a crisp click as it energises. No pull and no click, despite correct voltage and resistance, points back to the coil. A strong pull confirms the electrical side is working and directs your attention firmly to the valve mechanism.
Step 4 — Check the valve mechanism
With the electrics cleared, the remaining faults are mechanical. Common causes are dirt or scale trapped under the diaphragm or on the seat, a swollen or perished seal, a corroded armature, or a pilot orifice blocked by debris. Many valves have a manual override — a small screw or lever that mechanically lifts the armature. Operating it lets you confirm whether the valve will pass flow at all independently of the coil: if it opens on manual override but not electrically, the fault is electrical; if it will not open even on override, the obstruction or wear is inside the valve.
Remember, too, that most solenoid valves need a minimum pressure differential across them to shift and stay open. A pilot-operated valve tested on the bench with no pressure may not appear to open fully even when it is perfectly healthy, so interpret bench tests accordingly.
Coil or complete valve — deciding what to replace
Once you know whether the fault is electrical or mechanical, the replacement decision is straightforward. A failed coil with a sound valve body is an inexpensive, quick fix — coils are readily interchangeable by voltage and size, and our solenoid coil selection guide explains how to identify the right one. Where the seals, diaphragm or seat are worn, a service kit often restores the valve. If the body is corroded or the valve was simply wrong for the duty, it is worth reviewing the specification before buying again; the media, pressure range, port size and materials all matter, as covered in our guide to choosing a solenoid valve.
Quick testing checklist
In short, to test a solenoid valve: isolate and depressurise; confirm rated voltage is reaching the coil terminals; measure coil resistance for a finite, sensible reading (open circuit or short means replace the coil); feel for magnetic pull and a click when energised; then operate the manual override to check the valve body will pass flow. Work through them in order and you will pinpoint the fault without guesswork.
If you are unsure of the correct coil resistance for your valve, need a replacement coil or seal kit, or want to check that a valve is right for your application before ordering, our technical team is happy to help — contact us with the valve markings and we will point you to the correct part.