What Happens if a Sprinkler Fuse Blows?

Fuse Damage

• A sprinkler fuse usually breaks because there was too much electricity coming into the system. When this happens, the fuse itself will break a small filament inside the tiny glass tube. The filament will leave behind two ends of a broken conductor, and the inside of the glass may be scorched black from the break. The body of the fuse should not be affected and can be removed from the sprinkler timer by pulling on either end of the tube with your hand.

Sprinkler Shutoff

• When a fuse breaks inside a sprinkler timer, the automatic system that turns the water on and off will cease to function properly. If there is more than one fuse protecting your sprinkler timer, some zones on the system may continue to work if only one fuse breaks, but usually a broken fuse means you need to replace the fuse before the sprinkler valves can receive a signal from the timer.

Solenoid Problems

• Each sprinkler timer is connected to a series of solenoids that are attached to the sprinkler valves. A solenoid pushes down on a small plunger to release water to the system after it receives an electric signal from the timer. A faulty solenoid may be the cause of the blown fuse. A solenoid that has a bad connection can cause an electrical short that burns out the fuse back at the timer. If that is the case, you must replace the solenoid and the fuse before the system will work properly.

Breaker Trip

• An electrical surge may not only blow out the fuse on your sprinkler timer but may also trip a breaker on the home's electric fuse box. When a fuse blows, check the condition of each breaker within the fuse box to see if any are in the "off" position. If a breaker is off, push the plastic tab to the "on" position to reset that breaker's line.