Solar borehole pump troubleshooting and repair
Introduction to solar borehole pump troubleshooting
A solar borehole pumping system may develop electrical, hydraulic, mechanical, or control-related faults during operation. Common complaints include a pump that fails to start, low water output, inconsistent flow, controller alarms, frequent shutdowns, and a storage tank that does not fill.
Correct diagnosis is important because similar symptoms can have different causes. A pump that delivers little water may have a worn impeller, but the problem could also be low solar input, excessive pumping head, a falling borehole water level, blocked pipework, or incorrect controller settings.
Pro-Logic Technologies Limited works with Hydrosol Drilling Solution on borehole-related enquiries and water pumping requirements. A systematic troubleshooting process can help identify the cause of a fault before repair or replacement equipment is selected.
How a solar borehole pumping system works
A typical solar borehole system consists of solar panels, a compatible pump controller, electrical cables, a submersible pump, a rising main pipe, and a storage tank or distribution network.
The solar panels produce electricity when exposed to sunlight. The controller regulates the available power and operates the pump according to the equipment's requirements. The pump moves water through the rising main to the delivery point.
Additional components may include tank-level switches, borehole water-level sensors, isolation devices, surge protection, and a booster pump.
A fault in any of these components can interrupt the water supply. Troubleshooting should therefore examine the complete system rather than immediately assuming the submersible pump has failed.
Common signs of a solar borehole pump fault
A solar borehole pump may show several symptoms when something is wrong.
- The pump does not start when sunlight is available.
- The controller displays a fault or warning.
- The pump starts but produces no water.
- Water output is lower than normal.
- Pumping stops unexpectedly.
- The storage tank takes longer than usual to fill.
- The pump repeatedly starts and stops.
- The system operates only under strong sunlight.
- The water supply contains unusual amounts of sediment.
- The motor, controller, cables, or connections show signs of overheating or damage.
These symptoms are useful starting points, but none identifies a single fault conclusively. Proper diagnosis requires checking the operating conditions, equipment specifications, and available measurements.
Troubleshooting a pump that does not start
If the pump does not start, first check whether the system has sufficient sunlight and whether the solar panels are free from significant shading. Weak solar input may prevent some controllers from starting or maintaining pump operation.
Next, check the controller's display or indicators for fault codes, low-voltage warnings, overload indications, or other alarms. The manufacturer's manual should be used to interpret the displayed status.
Other possible causes include a disconnected isolator, a damaged cable, an incompatible controller configuration, an activated tank-level switch, a low-water protection signal, or a motor fault.
Electrical measurements should only be performed by suitably qualified personnel using instruments rated for the circuit. Solar panels can produce hazardous DC voltage whenever sufficient sunlight is available.
Solar pump controller fault diagnosis
The controller regulates the pump's electrical operation. Depending on the model, it may provide motor control, maximum power point tracking, overload protection, temperature monitoring, dry-run detection, and sensor inputs.
A controller fault can result from unsuitable input voltage, excessive current, overheating, moisture ingress, damaged wiring, incorrect settings, or an internal component failure.
Diagnosis should begin by recording the fault code and comparing it with the manufacturer's documentation. The technician should then verify the solar array configuration, controller ratings, pump compatibility, cable condition, and relevant operating measurements.
Repeatedly resetting a controller without identifying the cause can lead to further damage. A replacement controller must match the pump motor, solar array, and intended operating conditions.
Checking the solar panel supply
Insufficient solar input can prevent a pump from starting or reduce its output. Possible causes include shading, dirty panels, damaged modules, loose connections, incorrect array configuration, or cable voltage drop.
The array should be inspected for physical damage, shading, loose mounting hardware, and deterioration of exposed cables or connectors.
Where electrical testing is necessary, the technician should compare measured voltage and current with the panel specifications and the controller's permitted operating range. Open-circuit voltage and operating voltage are different measurements and must be interpreted correctly.
Testing should be performed using suitable instruments and safe procedures. A solar array should not be disconnected or reconfigured under load unless the equipment and procedure explicitly permit it.
Troubleshooting low water output
Low output may result from a pump operating at a greater head than expected, a decline in borehole water level, a worn pumping mechanism, a blocked pipe, a leaking connection, or insufficient solar input.
The first step is to compare the current flow with previous measurements taken under similar conditions. Changes in sunlight and pumping water level should be considered before concluding that the pump has deteriorated.
The technician should check the controller status, solar input, pipework, delivery valves, tank inlet, and any filters in the system. The pumping water level may also need to be measured to determine whether the borehole is being drawn down excessively.
If the pump is operating outside its intended performance range, correcting the system design may be more appropriate than replacing the pump with another model.
Diagnosing a pump that runs but delivers no water
When the pump appears to operate but no water reaches the delivery point, possible causes include a very low borehole water level, a damaged pump, a disconnected or leaking rising main, a closed valve, or a blocked delivery line.
The technician should first determine whether the controller indicates normal operation or reports a fault. The delivery route should then be checked for closed valves, visible leaks, or other restrictions.
The borehole water level may need to be measured to confirm that the pump remains adequately submerged during operation.
A pump should not be left running indefinitely while delivering no water. Continued operation under unsuitable conditions can damage the equipment. Follow the manufacturer's shutdown and troubleshooting procedure, and have the system inspected if the cause is unclear.
Understanding borehole water levels
The static water level is the level measured when pumping has stopped and the borehole has recovered. The pumping water level is the level while water is being withdrawn at a specified rate.
The difference between these levels is known as drawdown. Excessive drawdown may indicate that the pumping rate is too high relative to the borehole's available yield, or that the water source has changed.
If the pumping water level falls too low, the pump may lose output or trigger dry-run protection. A low water level can also occur during seasonal changes or after prolonged pumping.
Comparing current water-level measurements with the original borehole records can help identify changes in performance. The pump should be operated within the borehole's sustainable capacity.
Troubleshooting repeated pump shutdowns
Repeated shutdowns may be caused by changing solar conditions, controller protection, excessive motor current, overheating, low borehole water levels, or an intermittent electrical connection.
The timing of the shutdown can provide useful clues. If it occurs mainly during cloud cover or early and late in the day, the available solar power may be insufficient for sustained operation. If it occurs after a period of pumping, water-level decline or thermal protection may be involved.
The technician should record the controller alarms, operating duration, water output, and relevant electrical readings. The solar array, cable connections, pump, and protective functions should then be assessed.
Repeatedly bypassing a protection function is unsafe and may cause serious equipment damage. The cause of the shutdown should be established before normal operation resumes.
Dry-running faults and protection
Dry running occurs when a pump operates without adequate water for its normal pumping function. It can result from excessive pumping, a low borehole water level, a failed sensor, or an inadequate water supply.
Some solar pump controllers detect possible dry-running conditions from electrical measurements, while other systems use dedicated water-level sensors. Detection methods vary by equipment and may require correct configuration.
If dry running is suspected, follow the manufacturer's shutdown procedure and allow the system to be checked. The technician should establish the water level, confirm the pump's installation position, and determine whether the pumping rate is appropriate.
Dry-run protection should be tested according to the manufacturer's instructions. The pump should not be deliberately run without water unless an approved test procedure specifically allows a safe simulation.
Troubleshooting overheating
Overheating may affect a pump motor, controller, inverter, or electrical connection. Possible causes include excessive current, unsuitable operating conditions, poor ventilation around electronic equipment, incorrect wiring, or a failing component.
A controller installed in direct sunlight or in an enclosure without adequate thermal management may exceed its permitted operating temperature. Electrical connections with excessive resistance can also generate heat.
If equipment becomes unusually hot, displays an overtemperature alarm, emits a burning smell, or shows visible damage, the system should be placed in a safe condition according to the manufacturer's instructions.
A qualified technician should inspect the installation, verify the equipment ratings, and measure relevant electrical parameters. Protective functions must not be bypassed to keep the system running.
Electrical cable and connection faults
Submersible pump cables operate in demanding conditions. They may be exposed to moisture, mechanical stress, movement during pump installation, and long cable runs that contribute to voltage drop.
A damaged cable or unsuitable underwater joint can cause intermittent operation, insulation failure, leakage current, or motor failure. Poor connections above ground may also create resistance and overheating.
Cable inspection should consider insulation condition, connection quality, cable sizing, voltage drop, and compatibility with the pump and controller.
Insulation resistance and other electrical tests should be conducted by qualified personnel using appropriate equipment and the manufacturer's procedure. The pump should be isolated before work begins, and the solar array should be handled according to its DC isolation requirements.
Controller alarms and fault codes
Different controller models use different fault codes. A particular code should never be interpreted without checking the correct manual for that model.
An alarm may indicate low input voltage, overcurrent, overheating, motor overload, dry-running conditions, sensor failure, or another problem. Some controllers also distinguish temporary operating conditions from faults requiring inspection.
Record the exact code, the time it appeared, the prevailing sunlight conditions, and what the pump was doing when the alarm occurred.
The technician should then follow the manufacturer's troubleshooting sequence. Replacing components based on a generic fault-code list can lead to unnecessary cost or leave the original problem unresolved.
Troubleshooting a tank that does not fill
A tank that fails to fill may be experiencing a pump fault, insufficient solar input, low borehole yield, a closed valve, blocked pipework, leakage, or a failed tank-level control.
Begin by confirming whether the pump is operating and whether the controller reports a fault. Check the water delivery route and inspect accessible pipes, valves, and connections for leakage or obstruction.
The tank-level sensor may be preventing the pump from starting, or the sensor may be faulty. The control arrangement should be checked against the manufacturer's wiring diagram.
If the pump runs normally but the tank fills slowly, measure the actual flow and compare it with the expected performance. The result can help distinguish a hydraulic problem from a control or electrical problem.
Diagnosing a faulty float switch
A float switch controls operation according to water level. If the switch is stuck, damaged, incorrectly positioned, or wired incorrectly, the pump may fail to start or may continue running when the tank is full.
The switch should be inspected for obstruction and mechanical damage. The sensor's electrical operation should be tested according to the manufacturer's procedure.
The technician must confirm that the switch is compatible with the controller and that the wiring matches the correct control diagram. A switch should not be connected directly to a motor circuit unless it is specifically rated and approved for that use.
Tank-level automation should also have suitable overflow arrangements because sensors and controls can fail.
Low pressure in the water distribution system
Low pressure at taps or irrigation outlets does not always indicate a faulty borehole pump. The cause may be an undersized distribution pipe, a low tank elevation, a leaking pipe, a blocked filter, a failing booster pump, or excessive simultaneous demand.
The borehole pump may be operating correctly while the distribution network fails to provide the required pressure.
Diagnosis should identify where pressure is lost. Measuring pressure at relevant points, inspecting valves and filters, and checking the booster system can help locate the problem.
The required pressure should be calculated from the system layout and intended use. Replacing the borehole pump without assessing the distribution network may not solve the complaint.
Water containing sand or sediment
An increase in sand or sediment may indicate a change in borehole conditions, excessive pumping, disturbed deposits, or another problem with the borehole construction or pump installation.
Sediment can accelerate wear in pumps that are not designed to handle the material and may block valves, filters, or irrigation equipment.
The cause should be investigated before the pump is operated continuously under the changed conditions. A borehole specialist may need to assess the water source, pumping rate, and available construction records.
Do not assume that a larger pump or a different solar array will solve a sediment problem. The hydraulic operating conditions and borehole condition must be considered.
Troubleshooting insufficient solar pumping hours
A solar pumping system may operate for fewer hours than expected because of shading, seasonal solar changes, controller settings, insufficient array capacity, or faults affecting the electrical supply.
The technician should compare operating records with the site's expected solar conditions. Panel orientation, dirt accumulation, new shadows, cable losses, and controller alarms should be checked.
The design should also distinguish between the number of daylight hours and the effective pumping hours at useful output. A pump may operate at reduced output during weaker sunlight, so total daylight duration is not the same as full-capacity pumping time.
If the system consistently fails to meet the daily water requirement, the designer may need to review the pump duty, array sizing, water storage, and intended operating schedule.
When to repair a solar pump controller
A controller may be repairable if the fault is identifiable and suitable components and technical support are available. However, repair is not always the most practical option.
The decision should consider the type of failure, equipment age, availability of parts, repair cost, warranty implications, and the reliability requirements of the water supply.
Before repairing or replacing a controller, verify that the solar array and pump are correctly configured. An external problem such as excessive input voltage, unsuitable wiring, moisture ingress, or motor overload can damage a replacement controller as well.
A replacement unit must be compatible with the pump motor, array configuration, and required control functions.
When to repair or replace a submersible pump
The decision depends on the fault, pump construction, availability of compatible parts, installation cost, and expected future reliability.
A repair may be practical for a pump with a replaceable worn component or a fault that can be corrected economically. Severe motor damage, extensive wear, or repeated failures may make replacement more appropriate.
The technician should first establish the reason for the failure. A pump damaged by dry running, excessive sand, electrical incompatibility, or unsuitable operation may fail again if the underlying cause remains unresolved.
A replacement pump should be selected for the required flow rate and total dynamic head, while respecting the borehole's sustainable yield. It must also fit the borehole and be compatible with the existing controller and solar array.
Repairing a damaged rising main
A damaged rising main can reduce water delivery or prevent water from reaching the tank. The fault may involve a leaking joint, a damaged pipe section, a failed connection, or a component that cannot withstand the operating pressure.
The repair method depends on the pipe material, diameter, pressure rating, location of the fault, and manufacturer's instructions.
Where the damaged section is below ground or inside the borehole, pump retrieval may be necessary. This work requires suitable lifting equipment and a safe procedure.
After repair, the system should be checked for leaks and tested under appropriate operating conditions. The technician should also determine whether the original failure resulted from unsuitable materials, installation stress, or excessive pressure.
Repairing faulty tank automation
A tank control fault may prevent the pump from starting when water is low or stopping when the tank is full. Potential causes include a damaged float switch, failed sensor, broken cable, incorrect controller settings, or an incompatible control interface.
The fault should be diagnosed using the manufacturer's control diagram and an appropriate test procedure.
Tank automation should be restored without bypassing important protective functions. If the pump must be placed in manual operation for testing, the procedure should include suitable supervision and a safe means of preventing overflow or dry running.
After the repair, the complete control sequence should be tested and the results recorded.
Repairing faults in solar array wiring
Solar array wiring faults can result from damaged insulation, loose connectors, water ingress, incorrect string configuration, or unsuitable cable sizing.
The technician should verify the array arrangement against the design drawings and equipment specifications. Electrical measurements should be compared with the panel ratings and controller requirements.
DC circuits require particular care because the array can remain energised in sunlight. Isolators, connectors, and protective equipment must be rated for the circuit.
After a repair, the installer should confirm correct polarity, secure connections, acceptable electrical readings, and normal controller operation before returning the system to service.
Safe troubleshooting procedures
Solar borehole troubleshooting involves electrical equipment, water, lifting operations, and sometimes work at height. A safe procedure is essential.
The system should be isolated according to the manufacturer's instructions before electrical work begins. Solar panels can continue producing voltage in daylight, so workers must understand the isolation arrangement and use suitable test equipment.
Pump retrieval should use appropriate lifting equipment and methods that protect the cable, pipe, and pump assembly. Heavy components should not be handled using improvised lifting points.
Protective devices must remain in service, and damaged equipment should not be operated merely to keep water flowing. Work should be performed by suitably qualified personnel.
Documenting repair work
A repair record should identify the reported symptom, equipment models, controller fault codes, inspection findings, measurements, work completed, and any components replaced.
Where possible, the record should include water flow, pumping water level, relevant electrical readings, and the conditions under which the system was tested.
This information helps establish a baseline for future inspections and can reveal recurring faults. It also makes it easier to distinguish a new problem from an earlier issue.
The customer should be informed of any remaining limitations, recommended maintenance, and conditions that could require further assessment.
Preventing repeat solar borehole pump faults
Preventive measures begin with correct pump selection and safe installation. The pump, controller, solar array, cable, rising main, and protective devices should be designed as a compatible system.
The borehole should be operated within its sustainable yield, and suitable dry-run protection should be installed and tested. Solar panels should be inspected for shading and damage, while controllers and cables should be checked for signs of overheating or deterioration.
Changes in flow, pressure, pumping duration, water level, and controller alarms should be recorded. Early investigation of unusual changes may prevent a small fault from developing into a major failure.
Maintenance intervals should follow manufacturer recommendations and reflect the importance of the water supply.
Estimating the cost of solar borehole pump repairs
Repair costs depend on the fault, equipment type, pump installation depth, cable length, access conditions, spare-parts availability, and the amount of testing required.
A controller replacement may require less physical work than retrieving a submersible pump from a deep borehole. A rising main failure may require specialist lifting equipment and additional labour.
A quotation should distinguish between diagnosis, labour, replacement parts, pump retrieval, reinstallation, and commissioning where applicable.
Customers should avoid selecting a repair solely by the lowest initial price. Correct diagnosis, compatible parts, safe workmanship, and verification of the repaired system are important to reducing repeat failures.
Information to prepare before requesting repair assistance
When reporting a fault, provide the equipment details and a clear description of the symptoms.
Useful information includes the pump model, controller model, solar panel specifications, borehole depth, known water levels, normal flow rate, current flow rate, controller fault code, and when the problem began.
Explain whether the pump fails to start, starts and stops, produces no water, or delivers less water than usual. If the problem occurs only during certain weather conditions, mention that as well.
Photographs of equipment labels and controller displays may help identify the system, but they do not replace electrical testing or hydraulic measurements where those are necessary.
Solar borehole pump troubleshooting and repair enquiries
Pro-Logic Technologies Limited works with Hydrosol Drilling Solution on borehole-related enquiries and water pumping requirements. Customers experiencing pump faults, controller alarms, low water output, tank-control problems, or irregular pumping can discuss the symptoms and the available system information.
The recommended repair should be based on the fault diagnosis, the pump's hydraulic duty, the borehole's sustainable yield, and the compatibility of the replacement equipment.
Contact: 0723763173
Website: https://prologictecnologies.co.ke
A systematic approach to solar borehole pump troubleshooting helps distinguish electrical faults from hydraulic and borehole-related problems. Safe diagnosis, compatible replacement parts, correct installation, and post-repair testing are essential to restoring reliable water delivery.