BURKERT 20050714 (Type 6281 EV) is a servo-assisted 2/2-way plunger-actuated diaphragm solenoid valve configured for normally closed (Circuit Function A) operation. Designed for controlling, shutting off, and dosing neutral media up to a maximum kinematic viscosity of 21 mm²/s, the valve operates with flow directed above the seat and requires a minimum differential pressure of 0.2 bar to open, supporting working pressures up to 16 bar (PN 16).

The valve body is constructed from brass with a 20 mm main orifice (DN20), G 3/4 internal thread ports, a 1.3 mm pilot control orifice, and an installation length of 80 mm. Fluid sealing is handled by EPDM seals on both the main seat and external joints, providing media containment for water and oil-free fluids across a temperature range of -30 °C to +100 °C. Electrical actuation is powered by a 230 V AC/DC coil (50/60 Hz for AC supply) equipped with factory-sealed 3,000 mm flying lead wiring made of crosslinked polyolefin (PO) copolymer, certified under ATEX and IECEx standards for explosion-hazardous gas (Zone 1) and dust (Zone 21) environments.

Technical Specifications

Parameter	Value
Article Number	20050714
Type / Generation	Type 6281 / EV
Valve Construction	Complete servo-assisted plunger valve
Circuit Function	A (2/2-way, normally closed, inlet port 1 P/NC)
Main Valve Orifice (DN)	20 mm (3/4")
Pilot Control Orifice	1.3 mm
Flow Capacity Kv (Water)	8.5 m³/h
Flow Capacity QNn (Gas)	9,100 l/min
Port Connection	Internal thread G 3/4
Operating Pressure Range	0.20 bar to 16.00 bar (PN 16)
Flow Direction	Above seat
Body Material	Brass
Sealing Material	EPDM (seat and exterior)
Medium Temperature Range	-30 °C to +100 °C
Ambient Temperature Range	-30 °C to +55 °C
Storage Temperature Range	-40 °C to +80 °C
Supply Voltage	230 V (AC/DC, 50/60 Hz)
Electrical Connection	Flying lead cable, 3,000 mm length, PO copolymer crosslinked
Ingress Protection	IP65
Explosion Protection Marking	II 2 G mb IIC T4 Gb; II 2 D mb IIIC T130 °C Db (single mounting)
Manual Override	None
Installation Length	80 mm

Operating Conditions and Media Compatibility

Type 6281 EV functions reliably when operating parameters remain within the limits defined on the rating plate and technical data sheet. Media viscosity must not exceed 21 mm²/s.

Seal Material	Permitted Media	Medium Temperature (PA Coil)	Medium Temperature (Epoxy Coil NA38)
EPDM	Cold and hot water, oil- and fat-free liquids	-30 °C to +90 °C	-30 °C to +100 °C
FKM	Peroxide solutions, hot oils without additives, diesel and heating oil without additives, washing lye	0 °C to +90 °C	0 °C to +120 °C
NBR	Cold and hot water	-10 °C to +80 °C	Not specified

Article 20050714 uses EPDM seals with an epoxy-encapsulated explosion-proof coil, permitting fluid temperatures up to +100 °C. The valve is also certified for acetylene applications.

Continuous Operation and Downtime Maintenance

Unless indicated otherwise on the type label, the solenoid actuator is rated for continuous operation. During prolonged system shutdowns, perform at least 1 to 2 switching actuations per day to maintain pilot diaphragm flexibility and core mobility. High switching frequencies combined with high operating pressures reduce overall diaphragm service life.

Type Label Identification

The rating plate contains essential operating limits and approval codes. Verify that site conditions match the rating plate before installation.

Position	Description	Position	Description
1	Type (6281)	7	Connection type (G 3/4)
2	Circuit function (A)	8	Coil power consumption (W)
3	Orifice (DN 20 mm)	9	Frequency (50/60 Hz)
4	Sealing material (EPDM)	10	Voltage (230 V)
5	Body material (Brass)	11	Manufacture code
6	Nominal pressure (PN 16 bar)	12	Article number (20050714)

Installation Guidelines

High Pressure and Electrical Safety

Before loosening pipe unions, fittings, or valves, shut off operating line pressure and completely vent all connected lines. Switch off electrical power to the system and lock it against accidental reactivation. Only authorized technical personnel equipped with appropriate tools may perform installation work.

Pre-Installation Preparation

1. Flush and clean all connected pipelines thoroughly to eliminate foreign particulate matter, weld slag, and pipe scale.
2. Install an upstream dirt trap or strainer with a mesh rating of ≤ 500 µm directly before the valve inlet.
3. The valve can be installed in any orientation, though positioning the solenoid actuator upright at the top is recommended.

Pipeline Mounting

• Align flow with the directional arrow cast or stamped onto the brass valve body.
• Use an open-end wrench placed exclusively on the designated flats of the brass valve body when threading into the pipeline.
• Do not use the solenoid housing as a lever arm, as excessive torque will damage the core guide tube and coil interface.

Electrical Connection

Article 20050714 is supplied with a factory-potted 3,000 mm crosslinked PO copolymer flying lead cable without an external plug connector. Connect conductors in accordance with applicable local electrical explosion-protection standards (ATEX/IECEx).

• Connect the protective ground conductor securely and verify electrical continuity between the solenoid housing and the brass valve body.
• Ensure the applied line voltage matches the 230 V rating marked on the nameplate within a ±10% tolerance band.

Solenoid Coil Mounting and Torque Specifications

Coil Overheating Risk

Never energize the solenoid coil when it is removed from the valve core guide tube. Operating the coil without the valve armature/core will cause immediate magnetic overheating, leading to coil destruction and fire risk.

Assembly Sequence

1. Slide the solenoid housing over core guide tube (2).
2. Verify the correct position of O-ring (3) and anti-twist device (4).
3. Thread fixing nut (1) onto the core guide tube.
4. Tighten the nut using an open-end wrench to the specified torque. Do not use pliers or pipe wrenches.
5. Check protective conductor continuity after completing assembly.

Solenoid Type	Solenoid Width	Tightening Torque
AC10	32 mm or 40 mm	5 Nm
AC19	42 mm	10 Nm

Escaping Medium Hazard

If a firmly tightened core guide nut is loosened or twisted during service, process media will leak under line pressure. Do not continue to turn or overtighten nuts once torqued.

Troubleshooting

If the valve fails to operate as intended, verify supply pressure, voltage, and pipeline cleanliness before disassembling components.

Malfunction	Possible Cause	Corrective Action
Valve does not actuate / open	Power supply interrupted or coil short-circuited	Check supply voltage, wiring leads, and coil continuity
	Core or armature guide area contaminated	Disassemble coil assembly and clean armature chamber
	Differential pressure outside allowable range	Adjust system pressure to meet the required 0.2 to 16 bar span
Valve does not close	Internal valve chamber or seat contaminated	Inspect valve seat, flush body, and remove deposits
	Pilot control bore in diaphragm blocked	Clean diaphragm pilot bore or replace diaphragm assembly

Spare Parts Ordering

Original Spare Parts Requirement

Unsuitable spare components compromise pressure containment and explosion protection. Use only original Bürkert replacement parts and seal kits.

Order spare parts kits by citing kit designation SET 1, SET 3, or SET 7 along with device article number 20050714.

Storage, Return, and Disposal

• Store the valve in its original packaging in a dry, dust-free area protected from UV radiation and direct sunlight, within a temperature range of -40 °C to +80 °C.
• Prior to returning any equipment to Bürkert for service or inspection, contact the local sales office to obtain a return authorization number. Devices cannot be inspected or repaired without an approved, signed Contamination Declaration.
• Separate electrical and electronic subassemblies from metallic valve components for environmentally sound disposal in compliance with regional WEEE regulations.