Proportion Valve Flow Jumping With a Slight Opening Change, Drifting After Six Months? NL-PRV-8 Solenoid Proportion Valve Flow Linearity & Hysteresis Endurance Bench Runs Eight Stations (pump test bench)

Gas water heaters and boilers showing fluctuating outlet temperature after six months of use often trace to the proportion valve. On tear-down the opening-to-flow relationship has drifted from the factory curve: hysteresis grows and linearity degrades, so the same opening delivers a different flow and the outlet temperature can no longer hold. Yet linearity, hysteresis and response time are rarely measured at incoming inspection, so the deviation survives until the machine misbehaves — or until the end user complains.

What the NL-PRV-8 solenoid proportion valve flow linearity and hysteresis bench measures

• Eight stations in parallel, stepping the opening (0-100%) on a set sequence while flow is logged point by point, auto-plotting the opening-flow characteristic (sharing the constant-pressure supply and flow-metering module of our pump test bench systems)
• Linearity, hysteresis and repeatability indices calculated automatically, with NG judgement when the factory curve is exceeded
• Step response and response-time testing to reproduce the machine’s temperature-tracking capability
• Continuous-cycle fatigue endurance, with drift point and cycle count recorded automatically
• Sealing and internal-leak checks, quantifying zero-position and full-position leakage
• Barcode and batch binding, with raw data exported per unit for batch comparison

Applicable standards

IEC 60730-2-8 (automatic electrical controls – electrically operated water valves), EN 161 (automatic shut-off valves for gas burners and gas appliances), GB 16914 (safety and technical conditions for gas-burning appliances) and GB 4706.1 (household appliances – general safety); acceptance criteria can follow the customer's standard.

Stations and throughput

Eight stations in parallel in a 24/7 design bring a single valve’s linearity and hysteresis measurement down from hours of point-by-point manual testing to about ten minutes, while fatigue endurance is completed within weeks — so incoming lots can be sampled batch by batch, stopping temperature drift before assembly.

Manufacturer

Guangdong Endurance Electronic Equipment Co., Ltd. — a non-standard testing equipment manufacturer of solenoid proportion valve flow linearity and hysteresis endurance benches, pump test bench and pump performance test systems, level sensor life test machines, dishwasher test equipment and washing machine test equipment.

Keywords: pump test bench, pump performance test, level sensor life test, dishwasher test equipment, washing machine test equipment.