- Electrical causes: Undervoltage or overvoltage, asymmetrical three-phase current, diminishing insulation resistance.
- Environmental impacts: High ambient temperatures, lack of ventilation or poor ventilation, high installation elevation (low air density).
- Mechanical causes: Too many switching cycles, flow rate too high or too low, high resistance to rotation due to damaged pump, high viscosity or density of the pumped medium, clogged or blocked pump.
Circuit breakers and fuses trip for numerous reasons: undervoltage, asymmetric three-phase current, a short circuit on the motor, incorrect wiring or faulty electrical connections, a worn or blocked pump. The viscosity or density of used liquid for the pump is over the standard specification.
However, the product may also be undersized for the application in question, and may be operating in excess of its nominal flow rate.
Water hammering is a pressure surge caused by a rapid change in flow velocity in the pipeline. This phenomenon is referred to as “water hammering” because the pressure surges are frequently accompanied by a noise that sounds as if the pipeline were being pounded with a hammer.
In well installations, water hammering generally occurs if 1. The non-return valve in the downpipe extending down from the pump is installed more than 9 m above the water level, or 2. The non-return valve installed in the downpipe extending down from the pump is leaky, while a non-return valve fitted above that level stays tight. In both cases, a partial vacuum is created in the downpipe. The next time the pump is started up, water fills the vacuum at high flow velocity and presses against the closed non-return valve and the stationary water column in the pipeline, thereby causing a pressure surge or water hammering.
This pressure surge may cause pipelines to burst and pipe joints to break, and may damage the pump and/or the motor. If pressure surges do occur, the system should be switched off, and the pump installer should be brought in to resolve the problem.