Which action is a valid first check when diagnosing a zone energizes but delivers no water?

Which action is a valid first check when diagnosing a zone energizes but delivers no water?

• A. Verify the 24V supply to the zone valve/solenoid
• B. Replace the plant material
• C. Increase zone run time
• D. Inspect sprinkler heads only

Answer: (A)

Verifying the 24V supply to the zone valve/solenoid is the best first step because the valve relies on that electrical signal to open. If the valve isn’t receiving the correct voltage or has a wiring issue, it may not actuate properly even if the controller is calling for the zone. Checking the power and wiring first helps confirm whether the problem is electrical rather than hydraulic or mechanical, saving time and narrowing the focus to the right area. If the 24V supply is present and solid, you can then move on to other potential causes like a mechanical jam in the valve, debris in the diaphragm, or downstream blockages. Replacing plant material, increasing run time, or inspecting sprinkler heads alone don’t address the underlying electrical signal issue and won’t reliably fix a zone that should be opening but isn’t delivering water.

Verifying the 24V supply to the zone valve/solenoid is the best first step because the valve relies on that electrical signal to open. If the valve isn’t receiving the correct voltage or has a wiring issue, it may not actuate properly even if the controller is calling for the zone. Checking the power and wiring first helps confirm whether the problem is electrical rather than hydraulic or mechanical, saving time and narrowing the focus to the right area.

If the 24V supply is present and solid, you can then move on to other potential causes like a mechanical jam in the valve, debris in the diaphragm, or downstream blockages. Replacing plant material, increasing run time, or inspecting sprinkler heads alone don’t address the underlying electrical signal issue and won’t reliably fix a zone that should be opening but isn’t delivering water.