​WATER BORE FAULT FINDING GUIDE

​Submersible Bore Pump Fault-Finding Guide

Submersible bore pump troubleshooting-
This guide will help identify the likely cause of a submersible bore pump problem and the information needed before arranging service.
​Many apparent pump faults stem from the power supply, a control or protection device, pressure-switch adjustment, a pressure tank, changing bore water levels, pipework, or valves. Checking the whole system can prevent unnecessary removal of a serviceable pump from the bore.
Important electrical safety warning-
Submersible pump systems operate with potentially lethal electrical voltages.
A pump that is not running may still be electrically live.
Always isolate the electrical supply before opening a pressure switch, controller, starter, junction box or control box.
Only a suitably qualified electrician or pump technician may perform electrical testing, disconnection, insulation-resistance testing, and repairs.
Three-wire motor control boxes contain capacitors that may retain a dangerous electrical charge after the power has been isolated.
Do not bypass pressure switches, level controls, overloads or pump-protection devices unless this is done temporarily by a qualified person for controlled diagnostic testing.
Never leave a safety or protection device bypassed.
Before starting-
Record the exact symptom:

• The pump will not start.
• The circuit breaker trips.
• The pump runs but delivers no water.
• The pump produces low flow or pressure.
• The pump will not switch off.
• The pump starts and stops repeatedly.
• The controller or protection device trips.
• The water contains sand, air or sediment.
• The pump is noisy or vibrating.

Also note whether the problem occurred suddenly or gradually, and whether it followed electrical work, plumbing changes, dry weather, extended pumping or a period when the system was not used.

1. Pump will not start-
Checks that can be made without opening electrical equipment-
Check:

• Is the main isolator switched on?
• Has a circuit breaker or safety switch tripped?
• Is there a power outage?
• Is a timer preventing operation?
• Is a tank, float or level switch calling for water?
• Is the pressure gauge below the normal pump starting pressure?
• Does the controller display a fault code or warning light?
• Has a low-water or dry-run protection device stopped the pump?
• Has a valve been closed or a control setting changed?

Some protection devices include an automatic restart delay to allow the bore to recover.
Record the displayed fault before resetting anything.
Reset a protection device only in accordance with its instructions. Repeatedly resetting a device without finding the cause may damage the pump or motor.
Electrical checks-
A qualified electrician should verify:

• supply voltage at the pump controller or starter;
• voltage entering and leaving the control device;
• operation of the pressure, float or level switch;
• overload and contactor condition;
• continuity of the drop cable and motor windings;
• motor winding resistance; and
• insulation resistance between the motor circuit and earth.

If power is available at the controller but not at the pump cable, the fault is likely to be in the controls, protection equipment, starter or above-ground wiring.
If the correct voltage is being supplied to the drop cable but the motor does not operate, the fault may be in the drop cable, cable joint, motor or pump.

2. Circuit breaker or safety switch trips-
A circuit breaker that trips again after being reset is indicating an electrical fault or overload. Do not continue resetting it.
Possible causes include:

• damaged above-ground wiring;
• water inside a junction box, switch or controller;
• damaged submersible drop cable;
• a failed underwater cable joint;
• an earth fault in the motor;
• a seized or overloaded pump;
• incorrect overload settings;
• low or unbalanced supply voltage;
• a failed capacitor or relay in a three-wire control box; or
• an incorrectly sized circuit breaker or cable.

A qualified electrician can disconnect the pump circuit from the control equipment and test the above-ground installation separately from the pump, drop cable and motor.
Insulation-resistance testing can help determine whether the fault is below ground.
Interpret the test results according to the motor and equipment manufacturer’s requirements.
If the below-ground circuit fails testing, you may need to remove the pump so the drop cable, cable joint, and motor can be tested separately.

3. Pump runs, but no water is delivered-
Switch the pump off if water is not produced within its normal delivery time.
Do not allow a submersible pump to run dry.
Possible causes include:

• the bore water level has fallen below the pump inlet;
• the bore has not recovered after extended pumping;
• the pump is airlocked or has lost water within the rising main;
• a valve is closed;
• a non-return valve is jammed or installed incorrectly;
• a filter, pipe or outlet is blocked;
• the rising main has split or disconnected;
• water is leaking from the rising main back into the bore;
• the pump shaft, coupling or impellers have failed;
• the pump is rotating in the wrong direction on a three-phase installation; or
• the motor is running but the pump section is damaged.

Listen at the bore head for water movement and observe whether the pressure gauge rises at all.
A pump can appear to be operating normally while all the pumped water escapes through a split pipe or failed connection inside the bore. If the motor is drawing power but there is no pressure or delivered flow, the rising main and pump may need to be removed and inspected.

4. Low water flow or low pressure-
Possible causes include:

• falling dynamic water level;
• poor bore recovery;
• seasonal reduction in available groundwater;
• worn or damaged pump impellers;
• incorrect pump selection;
• blocked pump inlet or screen;
• partially closed valve;
• blocked filter;
• restriction in the pipework;
• leaking rising main;
• damaged non-return valve;
• low or unbalanced voltage;
• incorrect three-phase rotation;
• undersized power cable causing excessive voltage drop; or
• additional pipe length, elevation or water demand added since installation.

Measure the flow rate and pressure rather than relying only on how the system feels.
Record:

• pressure with water flowing;
• pressure with all outlets closed;
• approximate flow rate;
• supply voltage while the pump is operating;
• motor current on each phase, where applicable;
• standing water level;
• dynamic water level while pumping; and
• how long the pump runs before performance drops.

If performance is initially normal and then declines during pumping, bore drawdown or poor recovery is a likely cause.

5. Pump will not switch off-
A pump that continues running does not necessarily have a faulty pressure switch.
The pump must produce enough pressure to reach the pressure switch’s cut-out setting.
If its maximum pressure is below that setting, the switch will correctly remain closed and the pump will continue running.
Check:

• Are all taps, valves and water outlets closed?
• Is there a leak in the system?
• Is the pressure gauge working?
• Does the pressure rise when the main outlet valve is closed?
• What is the maximum pressure reached?
• Is the pressure-switch cut-out set above the pump’s available pressure?
• Has the bore water level fallen during extended pumping?
• Is the rising main leaking inside the bore?
• Is a non-return valve leaking?
• Is a filter or pipe restricting the pump?
• Is the pump worn or damaged?

If the pump stops after the cut-out pressure is adjusted slightly lower, this generally shows that the switch is operating and that the previous setting was above the pressure currently available from the pump.
The setting should be checked when the bore is fully recovered and again after an extended pumping period.
Do not allow the pump to run indefinitely against a closed valve.
For detailed instructions, see our Pressure Switch Adjustment guide:
https://www.waterborepump.com.au/pressure-switch-adjustment.html

6. Pump starts and stops repeatedly-
Frequent starting and stopping is known as rapid cycling. It can damage the motor, pump, pressure switch, contactor and starting equipment.
Possible causes include:

• incorrect pressure-tank air charge;
• a waterlogged or damaged pressure tank;
• a tank that is too small for the pump;
• pressure-switch settings that are too close together;
• a blocked connection between the pipework and pressure switch;
• a leaking non-return valve;
• a leak in the water system;
• low water demand compared with pump output; or
• a control or level switch repeatedly opening and closing.

The pressure-tank air charge must be checked with:

• the electrical supply isolated;
• the pump switched off;
• all water pressure drained from the system; and
• the pressure gauge reading zero.

The tank pre-charge must then be set correctly in relation to the pressure switch’s cut-in setting and the tank manufacturer’s instructions.
Do not check or adjust the tank air pressure while the water system remains pressurised.

7. Controller or pump-protection device trips-
A protection device is intended to stop the pump before damage occurs. A trip is often evidence of another problem rather than a faulty controller.
Before resetting the controller, record:

• the fault code;
• warning lights or display message;
• how long the pump had been operating;
• whether water flow had reduced;
• whether the bore had been pumped heavily;
• supply voltage;
• motor current, where available; and
• the time before the fault occurred.

Common trip causes include:

• low bore water level;
• dry running;
• motor overload;
• blocked or seized pump;
• low voltage;
• phase loss or voltage imbalance;
• excessive starts;
• damaged cable or motor insulation;
• over-temperature; and
• incorrect controller settings.

Allow the bore and equipment to recover before carrying out a single reset in accordance with the controller instructions.
If the fault returns, stop the pump and investigate the cause. Repeated resets may defeat the protection the controller is providing.

8. Sand, air or sediment in the water-
Possible causes include:

• the pump is installed too close to the bottom of the bore;
• the bore screen or casing is damaged;
• the pumping rate exceeds the bore’s sustainable yield;
• the water level is falling close to the pump inlet;
• the bore is producing sand or formation material;
• a pipe connection is drawing air; or
• the bore requires redevelopment or cleaning.

Reduce or stop pumping if a significant amount of sand is present. Sand can rapidly wear pump impellers, diffusers, bearings and valves.
Record when the sand or air appears—for example, immediately at startup or only after extended pumping.

9. Noise or vibration-
Submersible bore pumps should normally operate without significant noise or vibration at the surface.
Possible causes include:

• loose pipework or bore-head fittings;
• a damaged or poorly supported rising main;
• a non-return valve opening and closing;
• rapid pressure cycling;
• pump cavitation;
• insufficient water above the pump;
• worn pump components;
• incorrect three-phase rotation; or
• mechanical damage inside the pump or motor.

Switch the pump off if there is severe vibration, grinding, repeated hammering or a sudden change in operating sound.

When the pump may need to be removed-
Removal may be necessary when testing indicates:

• an insulation fault in the motor, underwater joint or drop cable;
• an open-circuit motor or cable;
• a seized motor or pump;
• a split or disconnected rising main;
• a failed non-return valve located down the bore;
• damaged or worn pump components;
• continuing sand damage; or
• correct power is reaching the pump but it produces no pressure or flow.

Do not remove the pump until the above-ground supply, controls, pressure system and valves have been checked. Pulling a bore pump can be costly and may not identify the problem if the fault is elsewhere in the installation.

Information to provide when requesting assistance-
Please send us:

1. Pump make, model and motor size.
2. Single-phase or three-phase supply.
3. Bore depth and pump installation depth.
4. Standing water level, if known.
5. Dynamic water level while pumping, if known.
6. Pipe size and approximate pipe length.
7. Pressure at pump start and stop.
8. Maximum pressure reached.
9. Measured flow rate.
10. Controller model and any fault code displayed.
11. Electrical test results completed by your electrician.
12. When the problem began and whether it is constant or intermittent.
13. Clear photographs of the bore head, controller, pressure switch, pressure tank, pressure gauge and general pipework.
14. A short video showing the pressure gauge and controller while the fault occurs, where safe to obtain.

This information will help determine whether the problem is caused by the pump, motor, bore, electrical supply, controls, pressure system or pipework.
Technical assistance
Waterborepump Warehouse
Phone: 1300 727 042
Email: [email protected]
Our submersible pump technicians are based in South Australia and service Adelaide and the Adelaide Hills.
​We also provide technical support and access to service contacts throughout Australia.

FREE ADVICE CALL:  1300 727 042
Email: [email protected]