SPRINKLER PUMP TROUBLESHOOTING
 

Sprinkler Pump Troubleshooting

 

Sprinkler Pump Troubleshooting

 

Please use caution when checking anything electrical.  Pumps use 115 or 230 volts AC which can injure or kill.
Always turn off circuit breaker (or remove fuse) that feeds the pump before servicing or inspecting it.  Some of these troubleshooting items will involve voltage testing.  If you are not comfortable doing that, hire a professional electrician.

Symptom
Possible Cause
Corrective Actions To Check/Try
Pump won't start or run

System pressure has not dropped to switch's "On" or "Cut-in" pressure (valid only if controlling pump with a pressure switch)

Zone valve is not opening to allow water to move. Check/repair zone valve.

Fuse or circuit breaker in your fuse box or breaker box has blown or tripped.

Inspect wiring, pressure switch, and motor for a problem that would have tripped the breaker or popped the fuse.  Repair problem then replace fuse or reset breaker

Motor is set to incorrect voltage, or, voltage being fed to motor does not match the motor's rated voltage.

Many pumps have dual voltage motors.  Consult owners' manual to find how to set the pump to the correct voltage according to what the voltage is that it will actually be connected to.

Confirm that voltage you have connected to the motor is what the motor is rated for.

Voltage at pump motor is too low

Measure voltage at motor when it is trying to run.  Comapare to base voltage of what is supposed to go to motor.  If voltage at motor is more than 5% lower than base voltage, check for loose connections or wire that is too light in gauge for the horsepower nd length of wire.

Pressure switch contacts are dirty or burned (valid only if controlling pump with pressure switch)

Measure voltage on motor side of the switch to see if proper voltage is getting through.  If not, replace pressure switch

Power wires are loose / disconnected

Check voltage at motor (and/or pressure switch) to determine which wire(s) are loose and repair as needed.

Starting component of motor has failed

Test motor's capacitor and start contactor to see if they are good.  Replace as needed if not.

Motor has failed

If everything above tests OK, the motor may have failed.  You will need to replace the motor or pump unit.

Motor runs but no water is delivered at all

Pump has not been primed

Follow the directions in your owners' manual regarding priming the pump

Pump is sucking air

Your suction pipe may have small leaks at joints, etc. where air can be pulled in.  Entire length of suction pipe and all fittings must be completely air tight(One test method is to use plastic cling wrap and wrap every joint to temporarily seal air leaks.)

Depth-to-water in well is too deep for the particular model of pump you have

Depth-to-water is depth from where pump is down to surface of water. For all sprinkler & centrifugal pumps this distance cannot exceed 25'. 

Check valve is installed upside-down or is stuck closed

Check valve must be installed in direction of water flow according to the arrow on the valve.  Ensure the valve is able to open and allow flow.

Pump motor is running on wrong voltage

For dual-voltage motors, confirm that motor is set to same voltage that you have it connected to.

For single voltage motors, make sure you have connected the voltage the motor is built to accept.

Too much restriction in suction pipe

Using a suction pipe that is too narrow, too long, or has too many elbows in it can cause too much restriction for the pump to be able to pull through. Never use pipe that is narrower than the suction port.  Limit the number of elbows.  Keep the suction pipe as short as possible.  If you do have a long suction pipe, increase pipe size from that of the suction port size.

Check valve, tee, or elbow installed too close to inlet of pump

We recommend a straight section of pipe at the pump's suction port (between pump and first elbow, tee, or check valve) that is a minimum of ten times the pipe diameter.  Use 24" to be safe. Having an elbow, tee, check valve, or other disruption too close to the inlet of the pump can cause cavitation inside the pump.

Suction pipe is not far enough down into the water

Ensure that end of suction pipe is into the water far enough

End of suction pipe is down too far into source of water and is buried in mud or dirt

Make sure suction pipe is not too close to bottom of well, lake, etc. so that it cannot pick up mud, etc.

Suction pipe is frozen

Make sure suction pipe is not frozen due to exposure to cold.  Thaw pipes for the pump to work now.  Bury the pipes below frost line for permanent solution.

Pump runs for a short time, delivers water, but shuts off by itself

Voltage is too low causing motor to shut off due to thermal overload

Check voltage at pump while its running.  Compare to the base voltage it is being fed.  If voltage the pump is receiving is more than 5% below the base voltage inspect your wiring for loose connections or insufficient wire size (gauge)

Circuit breaker has popped or fuse has blown

Inspect pump for jammed impeller or other damageInspect pump for jammed impeller or other damage

Ensure that wire from breaker (fuse) box to pump is heavy enough gauge.  Replace as needed.

Power wires are touching or grounded where they connect in the motor.  Make sure they are not.

Pump is free-flowing.  Motor will draw more amps when pump is allowed to flow lots of water with no back-pressure.  Need to restrict the output to keep the pump within its designed performance range.

Pump moves water but not to its capacity

Pump is sucking air

Your suction pipe may have small leaks at joints, etc. where air can be pulled in.  Entire length of suction pipe and all fittings must be completely air tight(One test method is to use plastic cling wrap and wrap every joint to temporarily seal air leaks.)

Depth-to-water in well is deeper than thought

If the water's surface level in the well is down further than what was thought, the pump will not perform as though.

Motor is operating on wrong voltage

If motor is set to run on 230v but is only being fed 115v it will run at half speed and cannot move as much water.  Check motor label for proper voltage.  If dual-voltage motor, set voltage selector to match voltage that is actually connected to the motor.

Pump is cavitating

We recommend a straight section of pipe at the pump's suction port (between pump and first elbow, tee, or check valve) that is a minimum of ten times the pipe diameter.  Use 24" to be safe. Having an elbow, tee, check valve, or other disruption too close to the inlet of the pump can cause cavitation inside the pump.

If pump is flowing too much water with not enough back-pressure, cavitation can result.  Reduce number of heads or otherwise reduce pump's output.

Impeller and/or diffuser is worn

If all items above check as OK, overhaul pump:  Replace impeller, diffuser, and necessary seals & gaskets

Sprinkler heads do not put out the pattern they should (smaller than normal)

Pump is sucking air

Your suction pipe may have small leaks at joints, etc. where air can be pulled in.  Entire length of suction pipe and all fittings must be completely air tight.  (One test method is to use plastic cling wrap and wrap every joint to temporarily seal air leaks.) 

Another option is to put foamy shaving cream around every joint on suction side and run the system. Look for any place where the shaving cream sucks in or dimples in.  This indicates a suction leak that needs to be fixed.

Depth-to-water in well is deeper than thought

If the water's surface level in the well is down further than what was thought, the pump will not perform as thought.

Motor is operating on wrong voltage

If motor is set to run on 230v but is only being fed 115v it will run at half speed and cannot move as much water.  Check motor label for proper voltage.  If dual-voltage motor, set voltage selector to match voltage that is actually connected to the motor.

Sprinkler system or zone simply requires more water (GPM) than this pump can supply

Check performance table to find the pump's performance at the depth-to-water in your setup and the pressure required at the pump.  Adjust the number of heads in the zone, the GPM capacity of the heads, or split system into properly-sized zones to match the pump's performance.

Use a higher-horsepower model pump that will deliver more water

Pipes in system are too narrow

Narrow pipes create friction that causes lower pressure at the far end.  Using larger diameter pipes allows more pressure to reach the end of the system.  Replace piping with larger diameter pipe.

Restrictions in the piping causing pressure loss

Too many elbows, kinked pipe, rust or scale buildup in pipe, etc. can cause pressure loss and flow restriction.  Check pipe for obstructions, use 45's instead of 90's for elbows, etc.

Debris in sprinkler heads

If problem happened after you worked on piping, or if you do not have sufficient filtering on the pickup pipe from a lake, rust, pipe scale, sand or other debris may have been passed through the pump and is partially blocking the spray head.  You'll need to follow the directions of the sprinkler head manufacturer to clean out the heads.

Impeller and/or diffuser is worn

If all items above check as OK, overhaul pump:  Replace impeller, diffuser, and necessary seals & gaskets

Wrong choice of pump. 

If your system does not use a lot of water (GPM) but needs more pressure (PSI) the sprinkler pump will feel a lot of back-pressure.  You may need to consider switching to a shallow well jet pump that won't move as much water, but will build better pressure.

 

Pump moves water but not to its capacity

Pump is sucking air

Your suction pipe may have small leaks at joints, etc. where air can be pulled in.  Entire length of suction pipe and all fittings must be completely air tight(One test method is to use plastic cling wrap and wrap every joint to temporarily seal air leaks.)

Depth-to-water in well is deeper than thought

If the water's surface level in the well is down further than what was thought, the pump will not perform as though.

Motor is operating on wrong voltage

If motor is set to run on 230v but is only being fed 115v it will run at half speed and cannot move as much water.  Check motor label for proper voltage.  If dual-voltage motor, set voltage selector to match voltage that is actually connected to the motor.

Restrictions in pipe are limiting flow

Too many elbows, kinked pipe, rust or scale buildup in pipe, etc. can cause pressure loss and flow restriction.  Check pipe for obstructions, use 45's instead of 90's for elbows, etc.

Pump is not getting enough water from source

If drawing from a sand point, you may need to put down more points and tee them together.

If drawing from lake, suction screen may be partially blocked by debris or algae.

Impeller and/or diffuser is worn

If all items above check as OK, overhaul pump:  Replace impeller, diffuser, and necessary seals & gaskets

 
 
Pump is leaking
Pipe or plug is loose

Check that suction pipe, discharge pipe, and drain plugs are all taped with teflon tape and are tight.

Body clamp is loose and / or body o-ring is bad

Loosen, then re-tighten the stainless steel clamp that encircles the pump body.  Tap the pump body and clamp with a soft rubber mallet while tightening so the o-ring seats properly.  If leak persists, replace o-ring.

Mechanical shaft seal is bad

If water is running out at the open spot where motor meets pump body, mechanical shaft seal may be bad.  Replace shaft seal.

Pump body or seal plate is cracked

Inspect pump body and seal plate for cracks.  Replace cracked piece.

 
 
Pump loses prime

If pump loses prime when it is shut off, something is allowing the water out of the system.

Foot valve or check valve in suction line is not holding.  Replace valve.

Leaks in suction pipe can also allow water out. Check and repair leaks at joints, etc.

If pump loses prime while it is running, something is allowing air into impeller area of pump.

Check for suction side air leaks.  Entire length of suction pipe and all fittings must be completely air tight.  (One test method is to use plastic cling wrap and wrap every joint to temporarily seal air leaks.)

Water level of the water where you're pulling from is dropping below the suction pickup pipe. You'll need to put the suction pipe down further into the water.  If drawing from a lake, be sure end of suction pipe is below the water's surface by a MINIMUM amount equal to 6 times the pipe diameter in order to prevent a vortex.  Deeper is better.  (example:  2" diameter pipe needs to be a MINIMUM of  6 x 2  = 12 inches below water's surface)

Cavitation in pump is great enough to lose prime.  We recommend a minimum of 2' of straigh pipe at inlet to pump.  There should be no elbows, tees, check valves, etc. in the last two feet of pipe before the inlet of the pump. Cavitation can also be caused by running the pump with too much flow and not enough back-pressure.  Need to provide more back-pressure in this case.