Question
I have a Toro timer, Flotec pump with relay. When I go to perform a manual start on the system it blows the fuse. I disconnected all 6 zones from the timer still blows fuse. I wired the pump straight to the breaker wiring - it starts. Reconnect the relay wiring and it blows fuses again. This just happened after a friend was helping me weed eat areound my house with a powerful weedeater. I thought maybe he cut through one of the wires at the solenoids but found no exposed wires - besides I disconnected all of the zones before. Does it sound like a bad pump relay? HELP

Answer
Hi Tom

Does the system operate correctly at the scheduled watering start times and "act up" only during manual operation??

It could be a faulty relay switch, but if the system works without incident during regularly scheduled start times, then the switch would trip your breaker at that time as well.

If you still have the owner's manual, double check the wiring schematic that came with your relay switch and ensure there isn't a cross somewhere - either at the relay or at the pump.  The 'hot' wire at the switch needs to be wired to the appropriate 'hot' terminal at the pump.  

If the wiring configuration is sound, then a bad switch could be the issue.  If you have the experience and are comfortable doing this, you can test voltage levels at the switch.  Disconnect the pump and leave the power supply in tact at the relay switch, and with a multimeter check the output levels of the switch when you turn it on from the controller.  Remember the controller only sends 24v to the switch - just enough to bump it across the bridge to complete the circuit and send power to the pump.

You should also check & test the voltage levels of the power source. If all levels are acceptable then the switch is the issue.

Hope this helps

Tony