Does the Pressure limiting bypass valve with GW BSP, type VM30 require periodic adjustment or recalibration of the opening pressure?

Pressure limiting bypass valve with GW BSP, type VM30 does not require routine recalibration of the opening pressure during normal operation, provided it is functioning within specified conditions. The opening pressure is mechanically set by an adjustment screw (Allen key) and locked with a locking nut; once set, it remains stable under normal service. Periodic attention is recommended, however, in these situations: - after maintenance or disassembly that affects the adjustment screw or locking nut; - if the system shows signs of pressure drift, leakage, or inconsistent relief behaviour; - when the valve has been exposed to conditions beyond specifications (overpressure, contamination, extreme temperatures, corrosion); - as part of scheduled preventive maintenance in critical systems where precise pressure control is essential. Inspection checklist: check setting integrity (locking nut tight), verify no external damage or leaks, confirm system pressure against the set value with a calibrated gauge. If adjustment is needed, use the Allen key to reset the opening pressure and re-lock the nut. Follow manufacturer guidelines for torque/setting if available. Regular cleaning of hydraulic fluid and proper filtration will minimize need for readjustment.

How often should the Pressure limiting bypass valve with GW BSP, type VM30 be inspected for seal wear and possible replacement?

For the Pressure limiting bypass valve with GW BSP, type VM30, inspect seals (NBR) for wear and consider replacement at least every 12 months under normal operating conditions. Increase inspection frequency to every 3â6 months if the valve operates near its maximum working pressure (up to 350 bar for 1/4", 260 bar for 3/8" and 1/2"), in high-temperature environments approaching +90Â°C, in low-temperature cycling (-20Â°C to +90Â°C), with contaminated fluid, or under heavy-duty/continuous use. Also inspect after any pressure spike, leak, or abnormal performance (e.g., failure to open at set pressure). Replace seals immediately if hardening, cracking, swelling, leakage, or visible deterioration is found.

Can the Pressure limiting bypass valve with GW BSP, type VM30 be used with fluids other than standard hydraulic oil?

Pressure limiting bypass valve with GW BSP, type VM30 is designed primarily for standard hydraulic oils (mineral oils) as indicated by its materials and seals. Key points affecting compatibility with other fluids: - Sealing material: NBR (nitrile). compatible with mineral oils, many petroleum-based fluids and some synthetic oils, but not recommended for prolonged contact with strong polar fluids (e.g. glycol-based fluids), phosphate esters, some synthetic esters, ketones or certain aggressive solvents, which can swell, harden or degrade NBR. - Body and valve materials: galvanized steel and aluminum. generally corrosion-resistant to hydraulic oils, but may be attacked by highly water-containing fluids, strong acids/alkalis, or some aggressive synthetic fluids. - Temperature range: â20 Â°C to +90 Â°C. fluids that require service outside this range (or whose viscosity at temperature extremes prevents proper valve operation) are unsuitable. - Functional design: valve depends on fluid viscosity and compressibility for reliable opening/closing and leak characteristics. High-viscosity fluids, water-glycol mixes, or low-lubricity fluids can alter response and wear. Conclusion: You can use fluids other than standard hydraulic oil only if they are compatible with NBR seals, do not corrode galvanized steel/aluminum, and their viscosity and temperature behavior fit the valveâs operating range. For water-glycol, phosphate esters, synthetic esters or other non-mineral fluids, consult the fluid and seal manufacturers or the valve maker for confirmation; if required, use a valve with compatible seal material (e.g. FKM, EPDM) and suitable construction.

Pressure limiting bypass valve with GW BSP, type VM30

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Additional information

Material	AL – aluminum

VM30 relief valve limiting maximum oil pressure in hydraulic systems. Allows free flow of fluid between P connections. When pressure exceeds the set value, the T path opens and excess oil drains to the tank. The opening pressure value is set using a screw (adjustment with an Allen key, locked with a locking nut). The valve is equipped with mounting holes. Body material: galvanized steel (1/4″), aluminum (3/8″ and 1/2″). Valve material: galvanized steel. Sealing: NBR. Maximum working pressure: 350 bar (1/4″), 260 bar (3/8″ and 1/2″). Operating temperature: from -20°C to +90°C.

List of product variants

Article number	Product variant name	DN	BAR	Availability	Actions
DC-VM30-00-04	VM30 relief valve with 1/4" BSP thread, 35 l/min, 0-50 bar	-	350	In stock	Enquiry
DC-VM30-00-06	VM30 relief valve with 3/8" BSP thread, 35 l/min, 0-50 bar	-	260	In stock	Enquiry
DC-VM30-00-08	VM30 relief valve with 1/2" BSP thread, 35 l/min, 0-50 bar	-	260	In stock	Enquiry
DC-VM30-05-04	VM30 relief valve with 1/4" BSP thread, 35 l/min, 50-200 bar	-	350	In stock	Enquiry
DC-VM30-05-06	VM30 relief valve with 3/8" BSP thread, 35 l/min, 50-200 bar	-	260	In stock	Enquiry
DC-VM30-05-08	VM30 relief valve with 1/2" BSP thread, 35 l/min, 50-200 bar	-	260	In stock	Enquiry
DC-VM30-20-04	VM30 relief valve with 1/4" BSP thread, 35 l/min, 200-350 bar	-	350	In stock	Enquiry
DC-VM30-20-06	VM30 relief valve with 3/8" BSP thread, 35 l/min, 200-350 bar	-	260	In stock	Enquiry
DC-VM30-20-08	VM30 relief valve with 1/2" BSP thread, 35 l/min, 200-350 bar	-	260	In stock	Enquiry

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VM30 relief valve limiting maximum oil pressure in hydraulic systems. Allows free flow of fluid between P connections. When pressure exceeds the set value, the T path opens and excess oil drains to the tank. The opening pressure value is set using a screw (adjustment with an Allen key, locked with a locking nut). The valve is equipped with mounting holes. Body material: galvanized steel (1/4″), aluminum (3/8″ and 1/2″). Valve material: galvanized steel. Sealing: NBR. Maximum working pressure: 350 bar (1/4″), 260 bar (3/8″ and 1/2″). Operating temperature: from -20°C to +90°C.