You turn a valve, and pressure spikes. Then it sags. Then it’s fine… until shift change.
Sound familiar?
Inconsistent pressure is a top complaint we hear from plant teams. The good news – most issues trace back to a short list of culprits. You don’t need to be a rocket scientist to find them.
Let’s keep it plain and practical.
Think of a booster pump system as cruise control for water. You tell it the setpoint (say, 75 psi). Sensors read the actual pressure. The controller speeds up or slows down the pump to match demand. If any piece in that loop is dirty, broken, or mis-set, pressure moves up and down.
Clogged strainers or filters
Debris builds up.
Flow chokes.
Pressure at the discharge wobbles as demand rises.
Quick tell: big pressure difference between suction and discharge compared to last month.
Tired or mis-calibrated sensors
A failing pressure transducer lies to the controller.
The drive hunts.
You see “yo-yo” pressure.
If the reading on a mechanical gauge disagrees with the digital display, believe the gauge.
VFD settings that don’t match reality
If the variable frequency drive (VFD) is tuned for last year’s process (or a different pump), you’ll get overshoot and lag. Common issues: too-aggressive PID (Proportional, Integral, and Derivative) gains, wrong minimum speed, and no deadband.
Air in the suction
Entrained air = spongy system.
You’ll see rattling or cavitation noise, micro-bubbles at sight glasses, and pressure that can’t settle. Check for leaks on the suction side and low tank levels.
Wrong-sized pump
Oversized pumps hit setpoint, then surge. Undersized pumps can’t hold up at peak demand. Both create instability. If your valve is always half-shut to “tame” the pump, that’s a sizing red flag.
Bladder/diaphragm tank issues
If you use a hydro-pneumatic tank, low pre-charge, or a ruptured bladder, it causes rapid cycling and pressure swings. A $20 gauge check can save a $2,000 headache.
Sticky or mis-set valves
Half-closed isolation valves, worn check valves, or a control valve fighting the VFD will all create oscillations.
Power and wiring gremlins
Single-phasing, loose grounds, or electrical noise in the sensor cable can make a stable system look unstable.
Total time: five minutes. You now know if it’s a blockage, a sensor/control issue, or a hydraulic problem.
Also Read:
Choosing the Right Industrial Pump System for Canadian Operations
Fix now (low risk)
Call us in when
Keep it steady – simple habits
Steady pressure means better quality, fewer nuisance alarms, and lower energy use.
Need a hand stabilizing your water-pressure-booster pump system or chemical dosing loop? The Vissers Sales Corp team can assess, tune, or redesign the control strategy so your pressure holds rock-solid all day.
Canada toll-free 1-800-367-4180 or visit our industrial pump systems page to get started.
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