วันเสาร์ที่ 20 มีนาคม พ.ศ. 2553

Sprinkler System Troubleshooting - A Three Step Approach

1. Is the water turned on? The backflow device turned off? If you have a separate water meter, is it open? If you know where one of the sprinkler valves is located, open it manually to see if there is water in the sprinkler system. If you have a pump, is the power switch or breaker turned on? Are any manual valves closed? Did it rain recently and activate the rain sensor? If you have no water supply problems, go to step number two.

2. Do you have 120 volts to the controller? Open the controller and check the power connection terminals with a volt meter (only if you are comfortable in working with electricity). You should have a minimum of 26 volts on low voltage controllers. Keep in mind that there some pump start system timers that output 120 volts.  If you do not have power, check the power source. If it is an outside sprinkler timer, make sure the electrical breaker is on. If it is an indoor controller, check the 120 volt plug-in outlet.  If you have 120 volt power but no "24 volt" power in the controller, the problem either is the 120/24 step down transformer, or a fuse or circuit breaker. You can replace theses without replacing the entire sprinkler controller. However, if it the fuse or circuit breaker you more than likely have a short circuit in the field wiring. If you have power, start the controller on zone one and measure the voltage going to field wire number one at the field wire terminal. Place one probe from the volt meter on zone one terminal and the other probe on the common terminal. You should have a minimum of 26 volts.

3. Okay. Let's say you have water and power. Now we'll check the field wiring. Disconnect the rain sensor and place the field common directly on the controller common terminal.

With the rain sensor out of the circuit, using an ohm meter place one probe on the common wire and the other on zone one. The valve resistance (ohms) should read between 20 - 60 ohms. If you have a master valve on your system, check that too. The master valve terminal will be labeled MV or PS for pump start.

If all the zones read much above 60 ohms, you have a problem with the common wire. The first place to look for this problem is where the field wires enter the ground after leaving the controller. Often you will find wire splices in this area. The next place to look is at the first valve electrically downstream from the controller. Sometimes all the valves are grouped together. A common location for this valve grouping is close to the irrigation back flow preventor. If you do not know where your valves are located you may need a wire tracker.  When the valve(s) are found, check the voltage going to the valve and ohm reading of the solenoid. Often just re-splicing the common wire connection will solve the problem.

This systematic approach to troubleshooting your sprinkler system should provide you with the information you need to repair your lawn irrigation problems.

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