Pump Commissioning
Pre start checks, priming and venting, first run and the readings worth writing down on day one.
Before the First Start
- Turn the shaft by hand. It should rotate freely with no rubbing or tight spots.
- Check that the coupling guard is fitted and that the alignment record has been signed off.
- Check the bearing lubrication. Grease lubricated bearings, as used on the KCP and VNP series, should be charged to the quantity given in the manual and no more. Over greasing runs bearings hot.
- Check that the suction strainer is clean and that any temporary construction strainer is fitted for the first hours of running.
Priming and Venting
- A centrifugal pump must be full of liquid before it starts. Running dry damages the mechanical seal in seconds.
- Fill the pump and the suction line and vent the casing at the high point until liquid appears with no air.
- On a flooded suction, open the suction valve fully and vent. On a suction lift, prime through the priming connection with the discharge valve shut.
- A wet installed vertical sump pump does not need priming. The hydraulic end is already below liquid level.
Starting
- Open the suction valve fully. It stays fully open in service — a centrifugal pump is never throttled on the suction side.
- Start against a closed or partly closed discharge valve, then open the discharge valve to bring the pump to its duty point.
- Do not leave the pump running against a fully closed discharge valve. With no flow, the power going in turns into heat in the casing.
First Run Checks
- Watch the discharge pressure and the flow settle. Compare them against the duty point on the order.
- Check the shaft seal. A single mechanical seal should show no visible leakage once it has run in. Gland packing, which is optional on the FA series, should drip slowly — a packed gland that runs dry burns the sleeve.
- Feel or measure the bearing housing temperature. It should rise and then hold steady.
- Listen for cavitation. A rattling sound like gravel in the casing means the available NPSH is below what the pump needs.
- Check the motor current against the nameplate.
Baseline Readings
- Write down the suction and discharge pressure, the flow, the motor current, the bearing temperature and the vibration level once the pump is running steadily.
- These first readings are the reference every later reading is compared against. Without them there is no way to tell whether the pump has drifted.
Commissioning FAQ
Should I start the pump with the discharge valve open or closed
Start against a closed or partly closed discharge valve, then open it to bring the pump onto its duty point.
Can I throttle the suction valve to reduce flow
No. Throttle on the discharge side only. Throttling the suction lowers the available NPSH and causes cavitation.
What does cavitation sound like
A rattling or crackling noise, often described as gravel passing through the casing, usually with unsteady discharge pressure.
Should gland packing leak
Yes, slowly. A packing gland needs a small continuous drip to lubricate and cool the packing. A mechanical seal should not leak.
Does a vertical sump pump need priming
No. On a wet installation the hydraulic end sits below the liquid level.
How long should the first run be
Long enough for the bearing temperature and the discharge pressure to stop changing, then record the readings.
Question About Commissioning
Send the pump series, the size and what you are seeing on site and we will come back to you.