How to Prime a Water Pump: Step by Step for Surface, Jet and Multistage Pumps
- Fill casing + suction
- No air bubbles
- Foot valve + airtight suction
- Never run dry
On this page
Why Does a Pump Need Priming?
Most surface pumps cannot pump air. If the casing or suction line is full of air, the impeller spins without moving water. Submersible pumps sit under water and do not need priming; surface centrifugal, jet and multistage pumps usually do, especially when they sit above the water level (suction lift).
Surface and Multistage Pumps at H-TECH
DAYLIFF DDV60KSh 8,410
DAYLIFF DC50PKSh 26,830
DAVEY JETPLUS JY350KSh 24,500
DAVEY XF171KSh 53,000
CNP CDLF2-11 Vertical Multistage Pump, 1.1Kw, Single PhaseKSh 85,000
CNP CDMF3-16 Vertical Multistage Pump, 1.5Kw, Single PhaseKSh 110,000
DAYLIFF FLOATSWITCHKSh 2,630| Product | Price |
|---|---|
| DAYLIFF DDV60 | KSh 8,410 |
| DAYLIFF DC50P | KSh 26,830 |
| DAVEY JETPLUS JY350 | KSh 24,500 |
| DAVEY XF171 | KSh 53,000 |
| CNP CDLF2-11 Vertical Multistage Pump, 1.1Kw, Single Phase | KSh 85,000 |
| CNP CDMF3-16 Vertical Multistage Pump, 1.5Kw, Single Phase | KSh 110,000 |
| DAYLIFF FLOATSWITCH | KSh 2,630 |
Current listed prices incl. VAT (updated 20 October 2026).
How to Prime a Centrifugal or Jet Pump
- Switch off and isolate the power.
- Close the outlet valve (if fitted) and open the priming plug on top of the pump.
- Pour clean water in slowly until the casing and suction pipe are full and water overflows without bubbles. Rock the pipe gently to release trapped air.
- Refit the priming plug firmly.
- Open the outlet valve slightly and switch on.
- If pressure does not build within a minute or two, switch off and repeat.
How to Prime a Vertical Multistage Pump
- Isolate the power and close the outlet valve.
- Remove the priming plug at the top of the pump head.
- Fill the pump through the plug hole until water flows out free of bubbles (with flooded suction, open the inlet valve and let water push the air out).
- Refit the plug, open the outlet valve slightly and start; check rotation direction on three-phase pumps.
- Open the vent screw briefly to release any remaining air, if the maker allows.
More on these pumps: vertical multistage pump guide.
Why Does My Pump Keep Losing Prime?
| Cause | Fix |
|---|---|
| Leaking or stuck foot valve | Clean or replace it |
| Air leak on suction joints | Reseal threads; tighten unions |
| Suction lift too high | Move pump closer to the water; consider a submersible |
| Suction pipe too small or with high points | Use the correct size, slope up steadily to the pump |
| Tank runs empty | Fit a float switch or dry-run protection |
For more symptoms see water pump troubleshooting; to choose the right type see jet vs centrifugal vs submersible.
Safety: electrical connections must be made by a qualified electrician, with correct earthing and a breaker sized for the equipment.
Frequently asked questions
How do I prime a water pump?
Isolate power, open the priming plug, fill the casing and suction with water until no bubbles appear, close the plug and start.
Why won't my pump prime?
Air leaks on the suction side, a faulty foot valve or too much suction lift.
Do submersible pumps need priming?
No, they sit under water.
How do I prime a vertical multistage pump?
Fill through the top priming plug (or open a flooded inlet) until water flows without bubbles, then start with the outlet slightly open.
Can a pump run without water?
No. Running dry damages the mechanical seal and impeller.