- Weak flow? – The impeller is probably clogged or damaged. Clean the line and check for obstructions.
- Motor on, but no water? – Air lock or a damaged shaft. Check the motor coupling and prime the line.
- Motor trips? – Motor overheating or unstable voltage. Get a voltage stabilizer installed.
- Vibration or noise? – Cavitation or misalignment. Check installation depth and bearing wear.
- Pump cycling on and off? – Pressure switch or bladder tank failure. Replace as necessary.
Mastering the 5 Most Frequent Submersible Pump Challenges
Submersible pumps are silent heroes working deep underground to lift thousands of litres a day. When it breaks, the show is over. From irrigation to a domestic water supply, to offices and factories, submersible pump problems can be devastating. Here are the top five issues and how to avoid them.
ALSO CHECK – Why Does My Submersible Pump Keep Tripping? (Causes & Fixes)
1. Clogged Impeller, Weak Flow
What Happens: Impeller clogged with sand, grit, or debris – your pump loses its prime, flow is weak, the tank fills slowly, or the pump loses pressure midway through the cycle.
Why It Happens: Pumps without sand filters continually draw in fine particles from sandy groundwater.
How to Avoid It:
- Install a sand filter/screen at the inlet
- Use stainless steel or thermoplastic pumps in sediment-laden water
- Backflush every 3-6 months
Select a pump that can handle your water’s particle size
2. Motor Burnout from Voltage Issues
What happens: The motor has to work harder to overcome low voltage, drawing more current than it was designed for, causing the windings to overheat and burn.
Why It Happens: Voltage sags in the grid due to poor grid stability, particularly during the peak irrigation months, strain single-phase motors.
How to Avoid It:
- Use a voltage stabilizer or motor pilot relay
- Have a control panel with an overload and lock-out relay
- Choose the right size submersible cables for depth and load
- Check phase balance on three-phase pumps
3. Cavitation – The Pump’s Silent Killer
What happens: Suction pressure becomes too low, water vapourises, bubbles form, and these bubbles implode in the pump – destroying impellers and casings in months.
Why It Happens: Improper depth, small pipe sizes, low water level, or operating the pump beyond its flow range.
How to Avoid It:
- Don’t operate the pump outside the desired flow and head
- Ensure the pump intake is never exposed during dry season drawdown
- Fit the right size uPVC riser pipes to reduce friction
- Don’t ignore rattling or crackling sounds
4. Dry Running – No Water to Pump
What happens: Without water, the motor loses its cooling source. Seals break, bearings overheat, and windings overheat – often in just a few minutes.
Why It Happens: Borewells dry out when water tables fall. The pump continues to run, unprotected.
How to Avoid It:
- Use a dry-run protection relay or float switch
- Install a control panel with a dry-run cutoff
- Measure the borewell water level annually before summer
- Use motors with thermal winding protection
5. Submersible Cable Electrical Faults
What Happens: Damaged insulation, incorrect cable size, or wet terminal joints lead to short circuits, motor trips, and eventual motor failure – making this one of the easiest submersible pump problems to avoid.
Why It Happens: Use of incorrect cable, underwater cable splices without waterproofing, damage during installation, or use of cables with insufficient conductor size for the depth.
How to Avoid It:
- Use cables designed for submersible use – withstanding pressure, moisture, and chemicals
- Never splice cables underwater; use rated waterproof junction kits
- Select cables based on motor current and installation depth
- Check the control panel terminals each year for signs of water ingress or corrosion
ALSO CHECK – Submersible Pump vs Centrifugal Pump: Which is Better for Your Needs?
Final Thought
To conclude, submersible pumps are built to work hard, but they’re not built to be ignored. The five issues we’ve covered above, clogged impellers, burnt motors, cavitation, dry running, and damaged cables, are responsible for the bulk of pump malfunctions in agriculture, domestic, and commercial installations around the globe.
The good news? All of them can be avoided with proper pump selection, installation, and routine maintenance.
Need help selecting a pump for your application? Tormac Pumps can help you select the right pump and provide after-sales support. Don’t wait until it breaks, choose the right pump today.
FAQs
- What are the most common malfunctions of submersible pumps?
- Dry running, motor burn-out due to voltage variations, and sand impingement or jam caused by debris are most frequent. Most of these problems can be avoided with a dry-run protection relay, voltage stabilizer and pre-sediment filter.
- How can I tell if my submersible pump problems are electrical or mechanical?
- Pump is running, no water = mechanical (blocked impeller or seal). Pump trips immediately or has a burning smell = electrical (cable or winding).
- When should I maintain my submersible pump?
- Every 6 months for a quick check: voltage, cable, and flow. Annually for a pump pull-out. Tormac Pumps suggests recording run hours and flow rates so you’re not surprised by performance declines.
