Assess pump health from field readings alone — no manufacturer curve required. Live calculations, nothing is saved.
Most pump assessment methods rely on comparing a test reading to the manufacturer's performance curve. That curve is often missing for older installations — so this tool works the other way round: it builds the pump's own apparent curve directly from your field measurements.
1. Differential head, not gauge pressure
The pump only "sees" the difference between what it's given (suction) and what it pushes out (discharge). Discharge pressure alone overstates the pump's effort if suction is pressurised, and understates it under suction lift. Every calculation here uses head = discharge − suction.
2. Curve fitting from your own points
Centrifugal pumps follow a predictable shape: head falls roughly as a curve (not a straight line) as flow rises. The tool fits a best-match curve (a quadratic regression, head = a + b·Q + c·Q²) through your measured points — the same family of curve a manufacturer would publish, just derived empirically instead of read off a datasheet. An R² score tells you how well your points actually agree with that shape; a low score means noisy readings or genuinely irregular behaviour, and conclusions should be treated cautiously.
3. Pump fault vs. test circuit resistance
Low flow during a bypass test can mean either a weak pump or a restrictive test loop — old pipework, excessive bends, a throttled valve, undersized hose, blocked strainer — both look identical as "flow was lower than expected." The tool tells these apart by checking where the shortfall shows up: if the fitted pump curve still has head in reserve at the flow you actually reached, the bottleneck is most likely downstream of the pump (the circuit). If the curve itself is already flattening out near that flow, the pump is the more likely limiting factor. A separate resistance coefficient (k, where loss = k·Q²) is also estimated purely from your points to characterise the test loop on its own — useful to compare against a repeat test later if the same bypass setup is reused. If the pump looks like it's underperforming, you can optionally enter the bypass pipe's diameter, length, material and fittings — the tool then calculates an independent friction-loss figure and compares it to the test-derived estimate. A large mismatch points to something not accounted for in those details (e.g. a valve left part-closed).
4. No fixed pass/fail threshold
Unlike a compliance check against a single named standard, this tool reasons in plain engineering terms — "curve shape is healthy," "speed varied across readings," "flow shortfall looks like circuit resistance" — because without a manufacturer curve there often isn't a single authoritative number to test against. Use it to support judgement, not replace it.
Nothing entered here is saved or transmitted — all calculations run in your browser and are lost when you leave the page.
If you know the pump's nameplate or design duty, enter it here for comparison. If not, the tool will still assess curve shape and trend from your measured points alone.
Record flow, suction and discharge pressure at each step as the bypass valve is throttled. Take at least 3–4 points across the range for a reliable curve fit — more points and a wider spread improve accuracy.
Only needed if the pump appears to be underperforming and you want to check whether old/restrictive bypass return pipework could explain it. If entered, an independent friction-loss estimate is calculated and compared against the resistance inferred from your test points — a mismatch suggests something not accounted for here (e.g. a valve not fully open).
Fittings in bypass return
Enter at least 3 measurement points to begin
All calculations update live — nothing is saved or submitted