Troubleshooting
Low pressure, stuck valves, dead zones, flickering lights, and controller error codes.
Why is one irrigation zone not working?
Manual-bleed the valve: if water flows, the valve body works and the issue is electrical (solenoid, wire, controller). If it does not, inspect the diaphragm and water supply to that valve. Also confirm the controller program includes that station with a non-zero runtime.
Why do I have low pressure on sprinklers?
Causes include too many heads on the zone, undersized pipe, partially closed valves, clogged filters/nozzles, a failing pump, or a leak. Compare design GPM to measured supply and walk the zone for geyser leaks or stuck-open valves elsewhere.
Why is water running when the system is off?
A valve stuck open, a leaking bleeder, or a leaking mainline/backflow can keep water moving. Shut the controller off and isolation valve to localize. Replace diaphragms/solenoids on the guilty zone valve once identified.
Controller shows a station on but valve does not open
Measure 24 VAC at the solenoid. Voltage present → replace solenoid or rebuild valve. No voltage → check station wire continuity, common wire, and controller fuse/transformer.
Sprinkler heads will not pop up
Low pressure, too many heads, or a debris-packed riser. Also check for a closed flow-control stem on the valve. Clean filters and verify zone GPM.
Brown spots in the lawn despite watering
Look for head spacing gaps, tilted heads, blocked nozzles, mismatched precipitation, or compacted soil. Catch-can tests reveal uneven application faster than guessing runtimes.
Irrigation system keeps tripping GFCI
Moisture in the transformer outlet, damaged cord, or a ground fault in line-voltage components. Low-voltage field wiring rarely trips GFCI unless the transformer itself is failing—have an electrician inspect the primary side.
Hydrawise program not watering
Confirm the controller is online, programs are enabled, rain/weather delays are clear, and zone runtimes are non-zero. Check that a rain sensor is not holding the system off.
Valve chatters or hammers
Water hammer from fast closure or air in lines. Add arrestors where appropriate, ensure adequate flow, and purge air after repairs.
Landscape lights suddenly all dim
Transformer overload, photocell failing, or a shorted cable. Divide loads, inspect splices for corrosion, and measure secondary voltage under load.
One landscape light is out
Check the fixture lamp/LED module, local splice, and voltage at that fixture. Daisy-chain opens often kill everything downstream of a bad connector.
Zone waters at night then puddles in the morning
Runtime too long for soil infiltration—enable cycle-and-soak and verify heads are not over-pressured and misting onto hardscape that drains to low spots.
Backflow preventer is leaking
Some discharge during operation is normal on certain assemblies; continuous dumping or spit can mean a failed check. Call a certified tester—backflow repairs are regulated in many areas.
Irrigation runs at the wrong time of day
Verify controller clock and timezone (critical after power outages), check multiple start times, and confirm someone did not enable manual or test programs.
Two zones come on together unexpectedly
Look for crossed wires in the box, a melted common short, or multi-station programming on commercial controllers. Ohm out station wires to find shorts.
Controller clicks but nothing happens
The relay may be firing without field voltage—check fuse, transformer VA, and station output with a meter. Clicking alone is not proof of 24 VAC at the solenoid.
Water hammer when valves close
Slow the flow with valve flow control, add arrestors if code allows, and avoid instantaneous shutoff on long mainlines.
Mud boils near a head
Likely a fitting leak under the head or lateral. Dig carefully, repair with proper couplings, and recompact soil to prevent sinkholes.
Lights work at dusk then die an hour later
Photocell or timer schedule may be wrong, or thermal protection on an overloaded electronic transformer may be cycling. Log voltage and load.
Sensor terminal error on controller
Bypass the sensor temporarily to restore watering, then repair wiring or replace the sensor. Do not leave bypass on permanently if code requires shutoff devices.
Zone has white crusty deposits on heads
Hard-water scale—clean nozzles and consider filtration. Severe scale may need water treatment discussion for drip zones.