One sprinkler zone won't turn on

Q: One sprinkler zone won't turn on

In Canada, when one sprinkler zone won't turn on while the others do, the most common cause is the controller — that zone switched off in the program, or a seasonal/rain-sensor setting holding it back. Try running the zone manually first. If no zones run at all, suspect the controller's fuse or its plug-in transformer. A single dead zone that won't respond usually points to a failed valve solenoid or a cut, corroded, or disconnected valve wire — both inexpensive, low-voltage fixes. Early in the season, the main supply or backflow preventer may simply still be shut off. If you see a scorched transformer or smell burning at the outlet, stop and call a licensed electrician.

One dead zone while the rest of the yard waters is usually a small, local problem — a program setting, a stuck valve, or a nicked wire — not the whole system failing.

tuneWhat are you noticing?

Select anything that matches and the checklist below reorders to fit. Not sure? Skip it.

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Start here

In Canada, start at the controller. Use its manual or "test" mode to run just this zone for a minute — if it fires when commanded, the schedule was the problem: a zero run time, a paused controller, a seasonal adjustment, or a rain/soil sensor holding it back. Free to rule out, and the single most common reason one zone stays dark.

Ranked from real-world failure data. The order updates as you select what you’re noticing above.

Likely causes, in the order to check them

Showing the typical order

Beginner-friendly Doable, with care Safety-critical Call a pro

visibilityHow to check

warning Keep water away from the powered sideThe valve and solenoid run on low-voltage 24 V and are safe to handle, but the controller's transformer plugs into 120 V. Do the wet work at the valve, keep hands and water clear of the transformer and any outlet, and if the transformer or outlet looks scorched or smells hot, stop and treat it as the escalation above.

Command the zone to run at the controller. At the valve, turn the black solenoid a quarter-turn counter-clockwise (the manual bleed): if water flows this way but not on the controller's command, the solenoid or its wiring — not the valve body — is the suspect.
Snug the solenoid back down. Disconnect its two leads and set a multimeter to ohms across them: a healthy 24 V AC solenoid usually reads roughly 20–60 ohms. An open (infinite) or near-zero reading means the coil has failed.
If the solenoid reads in range, the problem is likely the wire feeding it — move on to the valve-wiring check rather than replacing a good solenoid.

buildmultimeter schedule15 min

handymanHow to fix it

Shut off the system water, unscrew the failed solenoid from the valve (it hand-threads out with the wires attached), thread in a matching replacement, and reconnect its two leads to the valve wires with waterproof connectors.

Turn off the irrigation supply so the valve isn't under pressure, and pause the controller.
Unscrew the old solenoid counter-clockwise out of the valve body; a little water in the chamber is normal. Cut its two leads free, keeping the wire tails long.
Thread in a solenoid that matches the valve brand and 24 V AC rating; snug it hand-tight plus a touch — do not force it, the threads are plastic.
Join each solenoid lead to a valve wire with a direct-burial waterproof connector, restore water and power, and command the zone to confirm it opens and closes cleanly.

schedule30 min savings$15–25

24 V irrigation valve solenoidMatch the valve brand/model (Rain Bird, Hunter, Toro, Orbit) — thread and coil rating vary

gavel Check your province first AB: homeowner may do this · BC: homeowner may do this · ON: homeowner may do this · PE: homeowner may do this · QC: homeowner may do this
Swapping a 24 V solenoid is low-voltage work generally permitted for homeowners; no province reserves it. Confirm the local rule before publishing.

visibilityHow to check

At the controller, check that this zone's wire and the common wire are seated tightly in their terminals — a wire backed half out of a terminal is a common, free find.
With the controller off, measure resistance from that zone's terminal to the common through the buried run: a good circuit reads roughly the solenoid's resistance (about 20–60 ohms). Infinite resistance means a break; a very low reading can mean a short.
Inspect any reachable splice — buried connections corrode and rodents chew them. Green, crusty, or bare copper at a splice is your answer.

buildmultimeterbuildscrewdriver schedule20 min

handymanHow to fix it

Reseat a loose wire at the controller, or cut out a corroded/broken splice and rejoin the run with direct-burial waterproof connectors. A break in the middle of a buried run may need a locator or a new wire pulled to the valve.

With the controller off, reseat both this zone's wire and the common in their terminals; test the zone. A loose terminal is the fastest, cheapest fix.
If a splice is corroded or broken, cut back to clean copper on both sides and strip about a centimetre of insulation.
Rejoin the conductors with direct-burial (gel-filled) waterproof connectors — ordinary indoor wire nuts corrode underground and fail again.
Restore power and run the zone. If the run still reads open with no reachable break, the buried wire is damaged and a new conductor should be pulled to the valve.

schedule45 min savings$10–20

Direct-burial waterproof wire connectorsGel-filled / DBY-DBR style rated for underground low-voltage splices

handymanHow to fix it

Open the system's main shutoff and turn the backflow preventer's valves back to the run position, then re-pressurize slowly. If the backflow device itself is cracked or leaking, it must be serviced or tested by whoever your province permits.

Find the system's main supply valve (often in a basement, pit, or near the backflow assembly) and confirm it's open.
On the backflow preventer, turn both ball valves and the small test cocks back to their normal run position — after winterizing they're often left angled/open to drain.
Open the supply slowly to avoid a pressure surge, then run the affected zone. If the backflow body is cracked, dripping, or was frost-damaged, stop and have it serviced by a permitted tester rather than forcing it.

schedule15 min savingsusually free

gavel Check your province first AB: homeowner may do this · BC: licensed professionals only · ON: permit + inspection required · PE: homeowner may do this · QC: licensed professionals only
Opening a closed supply or backflow shutoff is homeowner-permitted; testing or repairing the backflow assembly may require a certified tester — confirm the provincial/municipal rule.

warning The transformer side is 120 VEverything past the controller is low-voltage and safe to handle, but the transformer itself plugs into a 120 V outlet. Unplug it before you inspect or swap it, replace the controller's fuse only with the same rating, and if the transformer or outlet is scorched or smells hot, don't re-energize it — that's an electrician's call, not a reset.

sort

Why the list is in this order

We don’t sort by likelihood alone. We sort the way a good, honest tradesperson thinks: rule out the free, safe, common causes first. That’s why the cheap checks outrank the expensive repairs — and why anything dangerous gets a hard stop instead of a pep talk. The order exists to save you money, not to sell you anything.