Piston Type Pressure Reducing Valve

Piston-type pressure reducing valve：Automatic pressure regulation achieved through spring-piston force balancing; outlet pressure can be set by pre-rotating the adjustment screw; when the inlet pressure fluctuates, the valve automatically adjusts its throttling opening without the need for repeated manual adjustment; the piston motion pair offers good resistance to water hammer impact; however, impurities may easily cause jamming of the piston assembly; suitable for water supply and heating systems where the inlet pressure frequently fluctuates.

Screw-type pressure reducing valve：Pure screw-type mechanical throttling mechanism without a pressure feedback automatic balancing mechanism; each change in inlet pressure requires manual re-rotation of the screw to manually reset the outlet pressure; simple structure and low cost; superior resistance to contaminants compared to piston-type designs; ideal for pipelines where the inlet pressure remains stable over extended periods with negligible pressure fluctuations.

Yuanlun piston-type pressure reducing valve is spring-piston force-balance automatic pressure-reducing stabilizing valve, PN16 nominal pressure-rating, DN15-DN50 thread connection. Main body is forged brass, built-in stainless-steel/copper piston assembly, sealing gaskets and pre-load adjustment spring.

By pre-setting spring pre-compression via top adjustment screw to set target downstream pressure. When inlet pressure fluctuates, valve-downstream medium pressure acts on piston surface, counter-balances spring force, automatically modulates internal throttling opening, keeps outlet pressure staying within preset range, realizes pressure reduction and self-stabilization for downstream piping system.

Critical functional limitation：

1. This product is pressure-reducing stabilizing valve, NOT safety relief valve. It CANNOT replace over-pressure safety relief valve. Downstream system must be equipped with independent safety relief valve for over-pressure protection.
2. Standard EPDM-seal brass variant working temperature 5℃-90℃. Only for clean tap-water, glycol-mixed non-corrosive anti-freeze liquid. Strictly prohibited for steam, strong-corrosion chemical medium.
3. Piston-cylinder moving pair is sensitive to solid impurities. Valve-front filter-strainer is mandatory;rust/sand particles will jam piston assembly and cause pressure-regulation failure.

Suitable for residential & commercial domestic water-supply, HVAC heating-chilled-water hydronic circuits, light-industry neutral-medium piping with fluctuating inlet pressure.

Important note: Installation recommended to be completed by qualified plumbing / HVAC technicians. Install strictly following body-cast flow-direction arrow;suggest horizontal mounting;valve front-side install filter-strainer;install pressure gauges on both inlet and outlet sides for commissioning.

Durable Construction: Forged brass valve-body delivers good corrosion-resistance and mechanical strength. Stainless-steel / copper piston fitted with matched sealing gaskets, guarantees long-term reliable sealing performance inside cyclic pressure-fluctuation environment.

Auto-Pressure Stabilization & Precise Regulation: Adopt spring-piston force-balance feedback mechanism. After one-time setting target outlet pressure, valve automatically compensates inlet-pressure fluctuation, stably maintains downstream pressure within design scope, realizes accurate pressure-reduction and stabilization.

Robust PN16 Performance: PN16 pressure rating meets most domestic plumbing and HVAC hydronic-system working requirements, good adaptability for general-purpose piping-system conditions.

Important limitation：No over-pressure relief function;cannot substitute safety relief valve;dirt medium must add upstream filter-strainer;steam forbidden for standard variant.

Specifications

• Main Components & Function

Operating Principle

Piston-type pressure reducing valve operates on spring-piston force-balance feedback principle：

1. Pre-commissioning：Loosen top-cover lock-nut;rotate adjustment screw to compress or release adjustment spring, set pre-load spring force corresponding to target outlet pressure;lock lock-nut after setting completed.
2. Medium flows through valve following body-cast arrow direction. High-pressure inlet medium passes internal throttling orifice, pressure drops.
3. When inlet-pressure rises：Downstream pressure pushes piston upwards, compresses adjustment spring;piston movement reduces throttling opening, increases local pressure-loss, restrains outlet-pressure from rising.
4. When inlet-pressure drops：Spring pre-load pushes piston downwards, enlarges throttling opening, reduces local pressure-loss, prevents outlet-pressure from falling too low.
5. Continuous dynamic balance between downstream medium-pressure thrust and spring force automatically stabilizes outlet pressure within preset range, completes pressure-reduction + self-stabilization function.

Four critical operating reminders：

1. It is pressure-reducing stabilizing valve, NOT safety relief valve. It will NOT discharge medium when downstream pressure goes over set-point;downstream pipeline must install independent safety relief valve for over-pressure protection.
2. Piston-cylinder moving pair is extremely sensitive to solid particles. Upstream filter-strainer must be installed;without filter, rust/sand will jam piston and make pressure-regulation completely invalid.
3. Install strictly follow flow-direction arrow;recommended horizontal mounting. Vertical mounting is technically feasible but will slightly affect piston gravity balance performance.
4. Standard 5-90℃ EPDM-seal variant; steam is strictly forbidden.

• Residential & Commercial Building Domestic Water-Supply Systems

Use-case：Downstream pressure stabilization for municipal water-supply with fluctuating inlet water pressure;protect downstream sanitary ware, water-using appliances from high-pressure damage. Project value：One-time pressure setting;valve automatically compensates municipal inlet-pressure fluctuation, keeps household outlet pressure stable.

• HVAC Heating & Chilled-Water Hydronic Circuits

Use-case：Pressure reduction and stabilization for glycol-mixed heating / chilled-water loops with unstable inlet pressure. Project value：PN16 brass body adapts general HVAC hydronic-system requirements;reduce pressure impact on terminal heat-exchanger fittings.

Light-Industry Neutral-Medium Auxiliary Piping

Use-case：Pressure-reducing stabilization for light-industry clean neutral-liquid auxiliary piping with fluctuating inlet pressure. Project value：Spring-piston auto-feedback avoids frequent manual re-calibration when upstream pressure drifts.

Application exclusion：

1. Not for steam, strong-corrosion chemical fluid.
2. Not for medium carrying large-amount rust/sand solid particles;must add upstream filter-strainer.
3. Cannot replace safety relief valve;downstream must equip independent over-pressure relief protection.

• Pre-Installation Check

1. Confirm valve DN-size, thread-spec match pipeline port;carefully read body-cast medium-flow-direction arrow.
2. Confirm project safety scheme：downstream pipeline has independent safety relief valve installed.
3. Inspect brass valve-body, piston assembly, sealing gaskets and adjustment spring;reject cracked, deformed, piston-jammed components.
4. Prepare upstream filter-strainer;prepare inlet-side and outlet-side pressure-gauges for commissioning.
5. Clean pipeline interior;thoroughly flush pipeline to remove welding slag, rust scale and solid particles before valve mounting.
6. Prepare qualified PTFE-tape for thread-joint sealing.

• Installation Steps

1. Wind PTFE-tape 3-5 clockwise-turns on mating pipeline thread port.
2. Mount valve into pipeline;strictly align body-cast flow-arrow with actual medium-flow direction;prefer horizontal installation.
3. Apply wrench torque only on valve-body brass hex flats. Do NOT apply wrench force onto top adjustment-screw / bonnet assembly, to avoid distorting internal spring-piston assembly.
4. Install mandatory upstream filter-strainer;mount pressure gauges on inlet and outlet sides for pressure observation and commissioning.
5. Complete mechanical assembly;fill and pressurize system.
6. Commissioning：loosen top lock-nut;slowly rotate adjustment-screw to set target outlet pressure, observe outlet pressure gauge until reaching design value;tighten lock-nut to fix setting.
7. Run system, simulate inlet-pressure variation, verify outlet-pressure keeps stable;inspect thread-joint and bonnet mating-face for external leakage.

• Important Installation Notes

1. Installation recommended for qualified plumbing / HVAC technicians.
2. Install strictly follow flow-direction arrow;horizontal mounting preferred;vertical installation may degrade piston balance performance.
3. Upstream filter-strainer is mandatory to protect piston moving-pair;piston jamming risk without filter.
4. Do NOT wrench top adjustment-screw / bonnet;only torque valve-body hex flats.
5. This valve has zero over-pressure relief capability;downstream must install independent safety relief valve.
6. Standard variant only for clean water/glycol neutral-medium;steam / corrosive-medium need customized material variant.

Routine-Maintenance Suggestion

• Visual inspection for thread-joint / bonnet-cover external leakage;observe outlet-pressure stability: Quarterly during system operating-season - Clean upstream filter-strainer regularly according to water-quality condition: Monthly-Quarterly
• System annual overhaul: Isolate & disassemble valve;clean piston-cylinder chamber;inspect piston sealing-gasket and adjustment-spring ageing condition: Annually
• Replace fatigue spring / aged sealing-gasket when pressure-stabilization performance degrades: As-required
• If piston assembly is severely scratched and worn, recommend whole-valve replacement.

When purchasing piston-type pressure reducing valve：confirm DN-size, thread-spec, PN16 pressure-rating. Clarify project requirement：

Distinguish：piston-type auto-stabilizing vs screw-type manual throttling. If inlet-pressure fluctuates frequently select piston-type;if inlet-pressure keeps stable choose cheaper screw-type.

Safety critical point：this valve CANNOT function as safety relief valve. Downstream system must additionally order independent safety relief valve for over-pressure protection.

Medium requirement：only clean water/glycol non-corrosive liquid;dirty-medium must match upstream filter-strainer;steam / strong-corrosion medium need custom-made variant.

Installation：prefer horizontal mounting;reserve access space for top-screw pressure-setting and later-period disassembly maintenance.

Yuanlun piston-type pressure reducing valve is PN16 spring-piston force-balance auto-pressure-reducing stabilizing valve, DN15-DN50 size-range. Forged brass body, built-in stainless-steel/copper piston assembly, sealing gaskets and pre-load adjustment spring. One-time manual pre-set outlet-pressure via top adjustment-screw;spring-piston force-balance feedback automatically compensates inlet-pressure fluctuation to stabilize downstream pressure.

Functional boundaries：Only pressure-reduction & stabilization;NOT safety relief valve, downstream must equip independent over-pressure relief valve;upstream filter-strainer is mandatory to prevent piston-cylinder jam;standard variant 5-90℃ only for clean water/glycol non-corrosive liquid, steam prohibited. Widely-applied for residential-commercial water-supply, HVAC heating-chilled-water hydronic circuits and light-industry neutral-medium piping with fluctuating inlet-pressure. Sample-order supported for pre-project-evaluation, 15-day standard lead-time for worldwide plumbing-HVAC distributors and engineering-contractors.

Zhejiang Yuanlun Valve Co., Ltd. was founded in 2006, formerly known as Yuhuan Guohong Valve Co., Ltd. It is located in Yuhuan, Zhejiang Province, known as the "Valve Capital of China". After nearly two decades of stable development, Yuanlun Valve is a professional manufacturer for HVAC valves integrating R&D, production and sales. Our product portfolio covers floor heating systems, air-conditioning systems, domestic water valves, including ball valves, thermostatic valves, manifolds, check valves, stop valves, filter valves, angle valves, pipe fittings, corrugated pipes and other series.