Troubleshooting Sprinkler Systems
An irrigation system should work perfectly for many seasons without any trouble. However, every sprinkler system eventually malfunctions. Luckily changing a single part usually returns the system to full working condition. With a little troubleshooting advice, a homeowner can often repair their own sprinkler system without calling a professional contractor.
A sprinkler system consists of a few basic parts: a water source, pipes, timer, valves and the sprinklers. Many homes use city water as the water source, while others take advantage of a well or lake. A home using a lake or well as its water source needs a high-voltage pump. A timer wires directly to the pump motor. When the timer activates, the pump motor draws water from the source and forces it into the irrigation pipes. A sprinkler system connected to city water uses a low-voltage timer. A low-voltage timer's transformer taps into the home's 120-volt circuit. The transformer converts high voltage into the low voltage power source the system requires. When the timer activates a zone, it sends the low voltage power source to the appropriate valve solenoid. Once activated the solenoid opens the valve, letting the water pass. Once it reaches the sprinkler heads, it is distributed across the landscaping.
Locating and Repairing Broken Sprinkler System Pipes
Eventually every sprinkler system suffers an underground broken pipe. Isolated areas of excessively moist soil, visible geysers and a water meter that runs with the sprinkler system off indicate that a sprinkler pipe has broken or cracked. In the worst cases, this problem can waste thousands of gallons of water each month. Finding the break often becomes frustrating. Common culprits include tree roots and careless shovel work.
If the break occurs before the valve, the broken pipe needs immediate attention. A break in this location leaks constantly and left unattended the damaged pipe will rupture. If a small area of the lawn turns exceptionally green or the soil seems spongy, check for a sprinkler pipe with a small leak. Once the pipe ruptures the constant water pressure bubbles up to the surface, clearly identifying the broken pipe's location.
Leaks after a valve will only appear when the timer activates the zone with the damaged pipe, resulting in a hard to find problem area. To find this type of leak, close or cap each sprinkler head and turn on the respective zone until the soil becomes wet. Carefully probe the wet area with a shovel to find the pipe. To close an adjustable fan-spray sprinkler head, pull up the sprinkler head's stem. Twist the top of the nozzle counterclockwise with one hand while holding the bottom of the nozzle still with your other hand. To close a rotor or gear driven sprinkler head, place the appropriate tool into the grove next to the arrow. Turn the adjustment screw counterclockwise. If the sprinkler head will not turn off, remove the soil surrounding the sprinkler head. Unscrew the sprinkler head from its male adapter. Place the correct sized threaded cap, either 1/2 or 3/4 inch NPT, on the exposed male adapter and hand tighten the cap.
The materials needed for repairing a broken or cracked sprinkler pipe include a can of wet-or-dry PVC cement, a small section of the correct size PVC pipe and a few fittings. Turn off the sprinkler system's water source. Remove at least 6 inches of soil underneath the broken pipe. Cut out the damaged section of pipe and let the residual water drain into the hole under the break. Clean the debris from the ends of the pipe. Replace the missing section of pipe, using the appropriate fittings and pipe. To avoid digging up large lengths of pipe, finish the repair with an expandable coupling or flexible tubing.
Repairing or Replacing Damaged Sprinkler Heads
Broken and incorrectly adjusted sprinkler heads do not distribute water correctly, leaving large areas of a lawn dry. Returning a sprinkler head to its proper adjustment setting often fixes the problem. Due to a new sprinkler head's relatively low cost and the variations between manufacturers, homeowners often find a complete replacement of a broken sprinkler head the easiest and most cost effective solution.
All fan spray sprinkler heads have a distance adjustment screw, the screw located on the top of the nozzle. Many nozzles throw water between 10 and 15 feet, assuming 25 PSI of water pressure at the nozzle. Turning the distance screw clockwise increases the water throw. Twisting the top of an adjustable nozzle changes the arc. Rotor sprinkler heads have distance and arc adjustments. The adjustment procedure depends on the manufacturer. Some manufacturers supply an adjustment key, while others use a small slotted screwdriver.
Lawnmowers cause extreme damage to a sprinkler head. Cement landscaping donuts help prevent the lawnmower blade from hitting the sprinkler head. If the lawnmower broke the sprinkler head's body, replace the entire sprinkler head with an exact replacement. If the lawnmower blade damaged the top of the sprinkler head, either replace the entire sprinkler head or try to identify the brand of sprinkler head and replace just the broken part from a new head. Replacing a broken cap and stem, sometimes called the shaft, eliminates the need to dig up the body.
Automobiles often drive over sprinkler heads positioned next to a driveway, usually breaking the sprinkler head or pipe below. Often the best solution involves digging up the sprinkler pipe and replacing the short section of hard PVC directly below the sprinkler head with a flexible PVC pipe, then installing an exact replacement sprinkler head.
When a sprinkler head's shaft extends but water does not spray out of the nozzle, debris has clogged the nozzle or its screen. Turn the system off and remove the nozzle and clean all debris from the nozzle's screen. To remove the a fan-spray sprinkler head nozzle, pull the stem up out of the body with one hand and grip the nozzle with the other. Hold the shaft still and turn the nozzle counterclockwise. Many rotor sprinkler head manufacturers use a nozzle that is locked in place with a set screw. To access the nozzle and set screw, unscrew and pull the rotor's cap and stem from its body.
A multimeter measures several different electrical readings. In most cases, homeowners only need a basic multimeter that reads voltage and resistance; professional technicians occasionally use the multimeter's other functions. Inexpensive digital meters simplify troubleshooting procedures.
One or More Zones Will Not Turn On or Stays On
A system with a zone that will not turn on or off has a malfunctioning timer, zone valve or a short in the low-voltage wire. Troubleshooting a low-voltage circuit requires a multimeter. A technician uses the multimeter to read voltage and continuity across the individual system parts, isolating the faulty device.
If the timer does not work at all, check the timer's transformer for proper input and discharge voltage. Some transformer's plug into a standard 120-volt receptacle, others are wired directly into the home's electrical circuit. If the transformer receives the proper voltage but its output voltage does not match its stated output voltage, replace the transformer. If the transformer works properly, replace the timer.
If only one zone will not turn on, check the timer's output voltage between the respective zone and common terminals. Activate the malfunctioning zone. Turn the multimeter to its lowest AC-voltage setting. Place one multimeter probe on the malfunctioning zone terminal and the other multimeter probe on the common terminal. Compare the multimeter readout with the timer transformer's stated output voltage. When activated, the timer allows low voltage to pass on the valve's solenoid. If the multimeter reads zero, replace the timer. If the multimeter shows voltage, turn off the timer and troubleshoot the valve's solenoid. Remove the wires connected to the valve's solenoid. Turn the multimeter to its resistance setting. Place a probe on each solenoid lead. If the solenoid does not have continuity, replace the solenoid. If the solenoid has continuity, check the low-voltage wires between the solenoid and the timer for a short. To check for a short, twist the two low-voltage wires at the solenoid together. Disconnect the common wire and the malfunctioning zone's wire at the timer. Using the multimeter, check for continuity through the wires. If the wires do not have continuity, replace the low voltage wires. If the wires do have continuity, reconnect everything. Tighten all electrical connections and test the zone.
If water seeps from the sprinkler heads in a particular zone after the timer turns off the zone, check the zone valve's diaphragm for debris or damage. To inspect a valve diaphragm, first turn off the irrigation system's water supply. Remove the valve's top. The removal procedure depends on the valve type and manufacturer. Lift the diaphragm and its spring from the valve body. Clean any debris from the valve body and inspect the diaphragm and spring for damage. Many home improvement stores sell replacement diaphragms for the various valve manufacturers.
High-Voltage Timer and Pump Issues
Because of the inherent dangers involved with high voltage, only individuals trained and experienced with high-voltage equipment should work on or repair the motor and timer. However, a basic understanding of how the system works never hurts. A sprinkler system drawing water directly from a pond or well usually uses a 240-volt pump motor, some systems operate on a 120-volt circuit. A dual voltage pump motor has a switch, located inside its electrical compartment, that allows operation with either voltage. Sprinkler systems that take water from a pond usually use a jet or transfer pump. Well pumps come in many configurations, including shallow well, deep well and submersible type pumps. Some systems use a pump start relay, while other pump motors are wired directly to a high-voltage timer. An irrigation system with a pump start relay uses the valve timer's low-voltage signal to turn on the pump motor. High voltage timers turn the pump motor on an off directly. Many submersible pumps need a start capacitor as well as a run capacitor. A capacitor holds voltage even after turning off the circuit breaker.
Some of the possible reasons that a pump motor will not turn on include a malfunctioning timer, incorrect voltage, faulty capacitor or a dead short. A dead short trips the pump motor's circuit breaker immediately. The dead short often occurs either in the motor's windings or along a stretch of a wire with worn insulation. The repair depends on the location of the short. A service technician always compares the actual voltage at the motor with the motor's stated operating voltage. If the irrigation system uses a dual-voltage pump motor, the technician will verify the motor's voltage setting. If the measured voltage and the stated voltage do not match, the technician will trace the electric supply back to the timer and then to the circuit breaker. If the measured voltage and the stated voltage match, the technician should test the capacitor before changing the motor.
How many months per year do you run your sprinkler system?
© 2013 Bert Holopaw