Replacing A Sprinkler Timer

A sprinkler timer can help your sprinkler system run more efficiently to keep your lawn and garden both colorful and healthy. You may need to occasionally replace a malfunctioning or outdated timer.

Is It Necessary?

Determine whether your timer is truly in need of replacing. A timer may not operate because of a circuit board failure, a blown fuse or a transformer failure. If the circuit board is the problem, replace the sprinkler timer. If the problem is with the transformer, only replace the transformer.

Write Down the Program

Make a log of the current program on the timer. This should include details about day of the week, start times and duration of water at each zone. The program can always be adjusted or reset at a later time.

Disconnect Power

Next, unplug the transformer to the wall. It might look similar to a cell phone charger.

If this is not feasible, turn off power at the breaker. Make sure that there is no electrical power to the controller. To make sure, a licensed electrician can check the power input wires. This is extremely important since electrical power can cause serious injuries or death.

Once it is guaranteed that power has been disconnected, locate the wires that control the sprinkler valves. They should be inside the controller. Remove the face of the timer to manage the wires.

Label Wires

Disconnect the field wires from the controller and label them. Remember that the two most important wires are the COMMON and the PUMP START wire.

Also, a wire will be marked by the letter 'C.' This is the common terminal in the controller.

There is also the Master Valve, labeled 'MV.' For some systems, this is called the pump start terminal, labeled 'PS.'

New Timer

The timer can now be replaced with the exact same model. When purchasing, ensure that the model and brand names match. There may be a color system for all the field wires. This can make the job easier so long as you have documentation regarding which wire coincides with which color.

Remove the used controller from the wall and replaced it with the new one. Ensure that the mount is in a position that will house the existing wire. Should the wires be too short to reach the connections, there are ways to extend the wires.
Now, reconnect the power wires. Restore power to the breaker or plug in the transformer. Once power is back on, the zone field wires should be connected. Test every zone to make sure it works.

Keep in mind that each system is subject to some variation.