How to Fix a Sprinkler System

Do-it-yourself solutions to irritating irrigation problems.

Next Project
Time

An hour or less

Complexity

Beginner

Cost

Less than $20

Introduction

These simple lawn irrigation system fixes will solve 90 percent of the common breakdowns. You'll save on repair bills and keep your lawn lush and green. No special skills needed.

Tools Required

  • 4-in-1 screwdriver
  • Hacksaw
  • Slip joint pliers
  • Spade
  • Wire stripper/cutter

Materials Required

  • Band clamps
  • Replacement heads and other parts
  • Tubing repair parts
  • Waterproof wire connectors

Project step-by-step (11)

Step 1

Replace a Sprinkler Head

  • Dig around the sprinkler head to expose the riser.
  • Unscrew the broken sprinkler head from the riser.
  • Install the new head, turning it tight with your hands.
Caution: Before you start digging to access the underground water lines, electrical wires or spray heads, dial 811 to have your underground utility lines identified and marked.

Replace a Sprinkler HeadFamily Handyman

Step 2

Clean and Reset Heads

  • Disassemble the sprinkler head by unscrewing the top from the canister.
  • Rinse away soil and debris in a bucket of water.
  • Remove the screen basket from the bottom of the head, then clean it with water.
  • Adjust the watering range of the sprinkler head before installing it. Make final adjustments with the water running.

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Step 3

Check the Valves

  • If you're experiencing low water pressure, check the sprinkler system valves on the backflow device to make sure they're open.
  • Turn the valve on the horizontal pipe first, then the vertical pipe valve.

Check the ValvesFamily Handyman

Step 4

Find and Repair Leaks

  • Before making the repair, make sure the system is turned off at the controller.
  • Cut out the damaged section of line.
  • Place a clamp on one of the line ends, insert a slip coupling, then tighten the clamp.
  • Place a clamp on the second pipe end, expand the coupling while inserting the nipple into the pipe, then tighten the clamp.

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Step 5

Repair Crushed Pipes

  • Dig along the water line until you find the damaged section. If the line runs near a tree, start your digging there.
  • Once you locate the damaged section, cut it out with a hacksaw.
  • If the line was damaged by tree roots, reroute the line by digging a new trench away from the tree.
  • Cut a new section of pipe to replace the damaged one.
  • Then replace the section of pipe, connecting it at each end with regular couplings and band clamps.

Repair Crushed PipesFamily Handyman

Step 6

Check for Low Voltage

  • Your watering system is divided into a series of zones.
    • Generally, if you have a zone that's not turning on, you have an electrical problem.
  • Make sure the zone wires are firmly attached to the terminals in the controller, the transformer is plugged in, and the circuit breaker at the main panel is on.
  • Next, test for voltage to the nonworking zone, using a multimeter.
  • Turn on the nonworking zone at the controller.
  • Turn the multimeter dial to voltage and place one lead on the common terminal.
    • The common terminal will be marked “c” or “com”
  • Place the other lead on the terminal of the zone that's not working.
    • Refer to your owner's manual to see whether the voltage reading falls within the required range (usually 24 to 28 volts).
      • If it doesn't, the controller needs to be replaced. 

Check for Low VoltageFamily Handyman

Step 7

Test the Transformer

  • Test the transformer voltage by placing the multimeter leads on the transformer terminals marked “24 vac” with the transformer plugged in.
    • If the reading is less than 22, replace the transformer.

Test the TransformerFamily Handyman

Step 8

Replace Sprinkler Solenoid

  • Disconnect the wires and unscrew the defective solenoid from the control valve. Insert a new one and turn it until it's finger-tight.

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Step 9

Reconnect the Wires

  • Connect the two wires on the new solenoid to the common wire and a field wire, using waterproof connectors.

Reconnect the WiresFamily Handyman

Step 10

Waterproof Connectors

  • Special connectors are filled with silicone to make the connections waterproof.
  • If the controller, fuse and transformer check out OK, test the resistance “ohms” between the common terminal and the nonworking zone.
  • Turn off the system, turn the multimeter to test for ohms (the omega symbol), and place the leads on the common terminal and zone terminal, just as you did to test for voltage.
  • Compare the ohms reading with the range listed in your owner's manual (usually 20 to 60 ohms).
    • If the ohms fall below the required amount, the switch (solenoid) that operates the control valve for that zone is defective and needs to be replaced. The defective solenoid will be connected to the same color wire as the zone wire at the controller.

Waterproof ConnectorsFamily Handyman

Step 11

Repair damaged wires

  • If the ohms reading between the common terminal and nonworking zone terminal is too high, the problem is a severed or bad wire to the control valve.
    • If only one zone isn't working, the field wire is damaged.
    • If none of the zones in a control valve box is working, the common wire is damaged, although the field wires could also be bad.
  • To find a bad wire, bypass each in turn by temporarily substituting a 14-gauge wire for the original that you run above ground.
  • Make the wire connections with the controller turned off. Then turn the controller back on.
  • Test the field wire first.
    • If the zone turns on, the old field wire is bad. Replace it with an 18-gauge wire rated for underground burial. Bury the wire at least eight inches underground.
  • Follow the same procedure to test the common wire.