BURKERT 20083344 (Type 6281) is a servo-assisted 2/2-way diaphragm solenoid valve engineered for fluid shut-off and dosing in hazardous operating environments. Configured in circuit function A (normally closed), the valve operates with a minimum differential pressure of 0.2 bar and provides positive shut-off up to 16 bar. The assembly features an investment-cast stainless steel 1.4408 (CF8M) valve body with G 3/8 internal thread connections, a 10 mm main orifice, FKM seals, and an explosion-proof coil system rated for 24 V AC/DC operation.

Designed for rigorous chemical, process, and gaseous oxygen installations, this specific part number is certified to ATEX and IECEx standards under encapsulation protection type Ex mb. It is degreased and free of oil and grease in accordance with DIS 1000020797, making it suitable for gaseous oxygen service (code NL02). Electrical connection is established via a factory-molded 3000 mm crosslinked PO copolymer cable, ensuring an IP65 degree of protection without requiring separate enclosure field wiring.

Technical Data and Operating Parameters

Type 6281 requires an operating differential pressure across the diaphragm to open and close. Full cross-sectional opening occurs once the differential pressure reaches 0.5 bar.

Technical Attribute	Specification
Product Type	6281 (Generation EV)
Article Number	20083344
Circuit Function	A (2/2-way, normally closed)
Port Connection	G 3/8 internal thread
Main Valve Orifice (DN)	10 mm (3/8")
Pilot Control Orifice	1.2 mm
Flow Factor Kv (Water)	1.9 m³/h
Flow Rate QNn (Gas)	2050 l/min
Nominal Pressure Rating	PN 16 (0.2 to 16.0 bar)
Operating Voltage	24 V AC/DC (50/60 Hz, tolerance ±10%)
Nominal Power (ATEX AC/DC)	7 W (coil width 32 mm)
Duty Cycle	100% ED continuous operation
Opening Time	0.1 to 1.5 s
Closing Time	0.2 to 4.0 s
Medium Temperature	0 °C to +60 °C (datasheet rating up to +90 °C for FKM in ATEX cable models)
Ambient Temperature	-30 °C to +55 °C
Ingress Protection	IP65 (with properly sealed connection)
Flow Direction	Above seat (marked by body flow arrow)
Manual Override	None

Differential Pressure Requirement

Servo-assisted diaphragm valves require a minimum differential pressure between the inlet and outlet ports of at least 0.2 bar to actuate. A differential pressure of 0.5 bar is required to fully open the 10 mm orifice cross-section.

Explosion Protection and Certifications

BURKERT 20083344 carries dual ATEX and IECEx certifications for use in gas and dust explosion-hazard atmospheres:

• ATEX Certificate: EPS 18 ATEX 1232 X
• ATEX Marking: II 2 G Ex mb IIC T4 Gb; II 2 D Ex mb IIIC T130 °C Db
• IECEx Certificate: IECEx EPS 18.0110 X
• IECEx Marking: Ex mb IIC T4 Gb; Ex mb IIIC T130 °C Db

Temperature Class Medium Limitation

According to the operating limits for explosion-protected valves, the maximum medium temperature must never exceed the permitted temperature class minus 5 K. For temperature class T4 (+135 °C), the process medium limit is +130 °C, subject to the +60 °C / +90 °C maximum rating of the selected FKM diaphragm material.

In addition to hazardous location certifications, the unit complies with manufacturer declarations for gaseous oxygen applications (code NL02) and has been cleaned free of combustible oils and lubricants according to DIS 1000020797.

Materials of Construction

Item No.	Element	Material
1	Solenoid Coil	Epoxy encapsulation (with FKM seals)
2	Stopper	Stainless steel 1.4113
3	Shading Ring	Silver (Ag) for stainless steel body variant
4	Magnetic Core / Plunger	Stainless steel 1.4113
5	O-Ring	FKM (Fluor rubber)
6	Core Seal	FKM (Fluor rubber)
7	Spring	Stainless steel 1.4310
8	O-Ring	FKM (Fluor rubber)
9	Diaphragm	FKM (Fluor rubber)
10	Diaphragm Holder	PPS-GF40
11	Valve Body	Stainless steel 1.4408 (CF8M)

Dimensions and Mechanical Interface

Dimensions for the Type 6281 DN 10 stainless steel ATEX cable version:

• Overall Height (B): 94.6 mm
• Valve Body Port Height (A): 83.6 mm
• Installation Length (L): 50.0 mm
• Body Width (C): 32.0 mm
• Bonnet Flange Dimension (D): 44.0 mm
• Port Center-to-Bottom (E): 22.0 mm
• Port Thread (G1): G 3/8 internal thread
• Thread Depth (F1): 12.0 mm
• Wrench Flat (SW): 22.0 mm
• Coil Width (H): 32.0 mm (Size 5)
• Coil Dimension (J): 20.5 mm
• Coil Length (K): 46.0 mm
• Coil Assembly Center-to-Edge (P): 68.8 mm
• Coil Height (R): 99.8 mm
• Overall Envelope (S): 174.7 mm
• Cable Length: 3000 mm (3.0 m)
• Unit Weight: 0.59 kg

Model Range and Ordering Data

Within the Type 6281 ATEX/IECEx cable series with circuit function A, stainless steel 1.4408 body, and FKM seal material, the standard ordering table identifies the following variants:

Port Connection	Orifice DN [mm]	Kv Value (Water) [m³/h]	Pressure Range [bar]	Weight [kg]	Article No. (024/AC/DC)	Article No. (230/AC/DC)
G 1/4	10	1.5	0.2 to 16	0.62	349665	349666
G 3/8	10	1.9	0.2 to 16	0.59	349669 / 20083344*	349670
G 1/2	13	3.8	0.2 to 16	0.84	349707	349708
G 3/4	20	8.5	0.2 to 16	1.20	349724	349727
G 1	25	12.0	0.2 to 16	1.60	349742	349744
G 1 1/4	25	12.0	0.2 to 16	1.70	349747	349750
G 1 1/2	40	30.0	0.2 to 16	3.10	349765	349767
G 2	40	30.0	0.2 to 16	3.30	349770	349771

Variant Distinction

Article number 20083344 corresponds to the 24 V AC/DC version with G 3/8 connection, stainless steel body, and FKM seals, supplied cleaned and degreased for gaseous oxygen service in accordance with code NL02 and DIS 1000020797.

Installation Guidelines

Proper mechanical and electrical installation ensures safe operation within hazardous locations.

• Mounting Position: Arbitrary orientation is permitted; mounting with the solenoid actuator upright is recommended.
• Flow Direction: Observe the flow arrow cast into the stainless steel body. The medium must enter port 1 (P).
• Upstream Filtration: Contaminants can plug internal pilot passages. Install a strainer or dirt trap with a mesh size of ≤ 500 µm upstream of the valve inlet.
• Mechanical Support: Never use the solenoid housing as a lever arm when tightening threaded connections. Hold the valve body firmly using an open-end wrench on the provided SW 22 mm flats.

Electrical Safety in Hazardous Locations

Isolate power and depressurize the piping system before starting installation, maintenance, or repair. Verify protective earth conductor continuity between the solenoid coil and the valve body before energizing.

Operation and Maintenance Instructions

• Continuous Duty Reliability: The solenoid is rated for 100% ED continuous operation. During extended non-operational periods, cycle the valve electrically 1 to 2 times daily to prevent plunger or diaphragm adhesion.
• Coil Mounting Safety: Connecting an unmounted coil to power will lead to rapid thermal overload and destroy the coil. The solenoid must only be energized after complete mechanical assembly on the valve core guide tube.
• Fixing Nut Tightening Torque: Tighten the solenoid fixing nut to 5 Nm (solenoid width 32 mm, type AC10) using an open-end wrench.
• Troubleshooting Non-Closing Valves: If the valve fails to close upon de-energization, inspect the diaphragm control bore for particulate obstruction, and verify that inlet pressure does not fall below the required 0.2 bar differential.