1. Overview
When a borehole pump won’t switch on, the issue is normally electrical, mechanical, or control-box related.
This guide helps homeowners, farmers, technicians, and installers troubleshoot step-by-step before replacing parts unnecessarily. Below is a troubleshooting guide.
Solar Drives For Borehole Pumps
2. Common Symptoms
- No sound or vibration from the pump
- No water flow
- Control box lights not coming on
- Circuit breaker keeps tripping
- Pump starts but immediately cuts off
- Pump hummings but doesn’t run (single-phase)
3. Step-by-Step Troubleshooting Guide
Step 1: Check Power Supply
Why?
Most borehole pump failures start with simple power issues.
What to check:
- Is Eskom/municipal power currently available?
- Does the DB board breaker trip when switched on?
- Test the socket or isolator with another device.
- Verify plug connections (if installed via a plug-top).
Quick Fixes
- Reset DB board breakers
- Tighten loose wires in the isolator
- Replace damaged plugs or sockets
- Avoid using extension leads (voltage drop risk)
Step 2: Inspect the Pump Control Box – Troubleshooting guide
(single-phase pumps: 0.37 kW – 2.2 kW)
Look for:
- Burnt smell
- Bulged capacitor
- Loose terminals
- Rust or water inside the control box
- Thermal overload tripped
Quick Fixes
- Reset the thermal overload
- Tighten all terminals
- Replace faulty capacitor
- Replace the entire control box if burnt or wet
Important: A failed capacitor is the #1 cause of a single-phase borehole pump not switching on.
Step 3: Test the Pressure Switch / Float Switch
Why it matters
If the switch does not send power to the pump, the pump will never start.
Check the following:
- Is the pressure switch stuck in the OFF position?
- Are the contacts burnt or not engaging?
- Float switch may be stuck in “empty” mode
- Incorrect wiring to the control box
Quick Fixes
- Manually toggle pressure switch
- Replace damaged pressure switch
- Loosen floats that may be stuck
- Rewire correctly as per pump diagram
Step 4: Check for Low Voltage or Voltage Drop
Signs of voltage problems
- Pump tries to start but hums
- Control box buzzing
- Lights dim when pump should switch on
Why this happens
- Undersized cable
- Long cable runs
- Poor rural supply
- Loose neutral/earth
Quick Fixes
- Measure voltage at the pump load side
- Upgrade cable thickness
- Repair damaged joints
- Install a voltage protection unit
Step 5: Inspect the Borehole Pump Motor Protections – Troubleshooting guide
If your installation includes:
- DOL starters
- Overload relays
- Motor protection breakers (MPB)
- VSD units
Check:
- Has the overload tripped?
- Are the settings too sensitive?
- Has the VSD gone into fault mode?
Quick Fixes
- Reset overload
- Increase trip setting slightly (within motor rating)
- Clear VSD fault and restart
Step 6: Check for Water Level Issues
Many modern systems protect pumps from dry-running.
Causes:
- Borehole water level dropped
- Float switch tripped
- Level sensors activated
Quick Fix:
- Wait for borehole to recover
- Bypass dry-run controller temporarily for testing
- Inspect floats for movement
Step 7: Wiring and Connection Problems
Loose or corroded joints cause pumps to fail to switch on.
Inspect:
- Junction box
- Submersible splice (blue heat-shrink join)
- Cable runs to control box
- Earth leakage
Quick Fix
- Re-do joins using proper resin kits
- Replace corroded connectors
- Ensure watertight seals
Step 8: Mechanical or Motor Failure
If all electrical checks are fine, the motor may be seized or burnt.
Symptoms:
- Pump hums but doesn’t run
- Breaker trips instantly
- No insulation resistance on motor
Confirm:
- Test motor windings with a multimeter
- Insulation resistance test (Megger)
Fix:
- Rewind motor
- Or replace the motor with new (often cheaper)
4. Quick Troubleshooting Table
| Problem | Likely Cause | Fix |
|---|---|---|
| Pump dead, no noises | No power / DB board trip | Reset breaker, check power |
| No lights on control box | Faulty control box | Replace capacitor or box |
| Pump hums only | Low voltage / bad capacitor | Fix voltage, replace capacitor |
| Pump runs but stops | Overload trip | Reset protection |
| No power reaching pump | Bad splice / broken cable | Re-splice or replace cable |
| Pump won’t start at all | Pressure switch fault | Replace or rewire switch |
5. When to Call a Technician
Call a professional if:
- You smell burning
- You hear buzzing at the control box
- Breaker trips repeatedly
- You see melted insulation
- Water entered the control box