Why is Our Water Pressure All Over the Place?

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.

What a Booster Pump System Actually Does

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.

The Usual Suspects

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.

A 5-minute checklist (No Laptop Needed)

1. Look
   • Is the suction strainer differential higher than usual?
   • Are any valves half-shut that should be wide open?
   • Any leaks, drips, or froth at sight glasses?
2. Listen
   • Rattling/gravel sound = cavitation.
   • Rhythmic on/off clicking = short cycling.
3. Compare
   • Mechanical gauge vs. HMI reading. If they differ by >5 psi, suspect the transducer.
   • Check last month’s shift log for normal suction/discharge numbers.
4. Feel
   • Suction pipe cold with condensation? You may be starved.
   • Motor hotter than usual? The pump might be working too hard.
5. Quick resets
   • Clean or swap the basket strainer.
   • Confirm tank pre-charge matches the setpoint (power off, system drained).
   • Toggle the VFD to “hand” and set a steady speed. If pressure stabilizes, the control loop is your culprit.

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

 

Easy Fixes vs. Call-a-Pro

Fix now (low risk)

• Clean strainers and filter elements.
• Tighten obvious suction-side fittings that weep.
• Replace a suspect pressure transducer (keep a spare).
• Restore VFD basics: correct setpoint, sensible min/max speed, small deadband (e.g., ±3 psi).

Call us in when

• Cavitation persists after cleaning and venting air.
• Pressure swings only at certain flows (likely tuning or sizing).
• You’ve got repeated short cycling (could be tank sizing or control valving).
• You run multiple pumps in lead/lag, and staging is chaotic.

Keep it steady – simple habits

• Log the numbers. One line per shift: suction psi, discharge psi, pump speed %. Drift shows up early.
• Schedule a strainer day. Pick a weekday and stick to it. Clean, inspect, re-gasket.
• Protect the sensor. Route transducer cables away from VFD power leads. Cheap ferrites help.
• Tune once per change. New process? New setpoint? Retune the PID. Don’t copy last year’s values.

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.