BURKERT 20079750 Type 8640 is a modular pneumatic valve island configured as a 12-station valve block. Designed with a 16.5 mm station pitch, this revision 3 assembly incorporates 12 integrated 5/2-way valve slices (circuit function H), a central G 3/8 supply port, and bottom-facing D8 push-in working connections. The valve block is engineered for direct DIN-rail mounting and operates across a pneumatic pressure range of 2.0 to 10.0 bar, utilizing individual discrete wiring without an internal fieldbus module.

Intended Use and Operating Safety

BURKERT 20079750 controls compressed air and neutral gases in industrial automation systems. Compatible media include filtered compressed air with maximum particle size of 10 μm (preferably unlubricated, though lubricated air is permitted) and neutral gases filtered to 5 μm.

Pressure and Electrical Safety

• Relieve system pressure and vent lines prior to servicing or loosening pneumatic connections.
• Fasten all hose connections securely before applying pressure to prevent hazards from flapping lines.
• Disconnect power and secure against reactivation prior to any electrical maintenance.
• Do not touch device surfaces during continuous operation without thermal protective gloves.

Electrostatic Protection (ESD)

The internal subassemblies contain electrostatic discharge sensitive components. Comply with EN 61340-5-1 handling procedures during installation and avoid touching electrical contact pins under voltage.

Structure and Component Design

The valve block is built on modular pneumatic base modules with snap-in latch mechanisms, carrying individual Type 5470 solenoid valves driven by Type 6106 3/2-way pilot stages.

Item	Designation
1	Pilot valve Type 6106
2	Exhaust port 3 (R)
3	Pressure port 1 (P)
4	Working port 4 (A)
5	Working port 2 (B)
6	Manual override switch
7	Cable plug interface (Type 2506 / 2516)

Pneumatic ports on the valve slices and modules follow standard industrial designations:

Connection Number	Port Function
1	Pressure supply port (P)
2 and 4	Working ports (B and A)
3	Exhaust port (R)
5	Secondary exhaust port (S)

Manual Override

Each valve station includes a mechanical manual override for commissioning and function testing without electrical excitation.

To lock the valve manually, press the manual override actuator and rotate it 90° clockwise until it hits the mechanical stop. The manual override remains mechanically detented and does not spring back automatically. Only actuate the manual override while electrical power is shut off.

Circuit Functions and 4/2 to 3/2 Conversion

Individual valve slices in Type 8640 can be operated in multiple configurations, including function C (3/2-way NC), function D (3/2-way NO), function G (4/2-way), and function H (5/2-way). On 4/2-way configurations, converting to 3/2-way operation is accomplished by sealing one working port with a blanking plug:

Working Port 2	Working Port 4	Resulting Circuit Function	Rest Position State
Closed (plugged)	Open	C (3/2-way NC)	Port 1 (P) closed, Port 4 (A) exhausted to Port 3 (R)
Open	Closed (plugged)	D (3/2-way NO)	Port 1 (P) connected to Port 2 (B), Port 3 (R) closed

Technical Data

Specification Parameter	Technical Value
Valve Island Type	Type 8640 (Revision 3)
Article Number (SKU)	20079750
Number of Valve Stations	12 valve slices
Valve Function	12x 5/2-way circuit function H
Station Pitch (Width)	16.5 mm
Pneumatic Supply Connection 1 (P)	G 3/8
Pneumatic Working Connections 2 (B) / 4 (A)	D8 push-in fittings (bottom pneumatic module)
Operating Pressure Range	2.0 bar to 10.0 bar
Pilot Pressure Requirement	2.0 to 10.0 bar (at least 70% of line operating pressure)
Minimum Pressure Differential (Port 1 to 3)	2.0 bar
Operating Medium	Compressed air (10 μm filtered), neutral gases (5 μm filtered)
Sealing Material	NBR
Medium Temperature Range	0 °C to 50 °C (air must be dried below 0 °C)
Ambient Temperature Range	0 °C to 55 °C
Integrated Exhaust Check Valves	Included on channels 3 (R) and 5 (S)
Pneumatic HotSwap at Port 1	No
Mounting Form	DIN-rail mounting (EN 50022 35x15 or 35x7.5)
Control Concept	Single discrete wiring per coil (no bus electronics)
Degree of Protection	IP20

Functional Reliability During Standstill

If continuous operation is interrupted, BURKERT recommends cycling each valve slice 1 to 2 times daily during idle periods to maintain reliable seat movement and lubrication.

Installation and Assembly

Solenoid Rotation

Valves are factory assembled. When orientation requires modification for specific cabinet layouts, the pilot coil can be unfastened and turned 180°:

1. Loosen the M2 mounting screw and detach the solenoid coil from the valve body.
2. Rotate the coil 180° and reseat it squarely onto the valve housing.
3. Tighten the M2 screw in two progressive stages: initial increment to 0.1 Nm (±0.05 Nm), followed by final torque of 0.2 Nm (±0.05 Nm).
4. Verify electrical continuity of the protective earth conductor path.

Modular Block Assembly

Base modules interlock via lower latch hooks (3) and upper latch tabs (2) joined to the left connection module (1) and right connection module (5):

1. Start assembly from the left supply module.
2. Inspect all module lateral channels; insert 2 sealing O-rings into each module face, lightly lubricating seals with pneumatic grease.
3. Hook lower module tabs into the adjoining grooves, align square, and press upward until upper latch hooks snap positively.
4. Fit 3 O-rings into the valve rear interface recesses. Seat profile seals accurately to prevent leakage across pressure supply channel 1 (P) and exhaust channel 3 (R).
5. Secure each valve body to the base module using two screws tightened to 0.6 ±0.1 Nm.

Mounting onto DIN Rail and Wall Surface

Item	Component Function
1	Electrical connector (rotatable by 180°)
2	Direct wall-mounting screw hole
3	Standard DIN rail (35 x 15 mm or 35 x 7.5 mm per EN 50022)
4	Pneumatic connection module

For DIN-rail mounting, place the upper mounting groove of the valve block over the rail, press the lower clamping blocks into place, and tighten clamping screws. For direct panel mounting, secure the module feet directly to a flat wall surface using M4 fasteners.

Port Connection Tightening Torques

Port Thread Size	Applicable Port Function	Recommended Torque [Nm]	Maximum Torque [Nm]
G 1/4 or NPT 1/4	Supply port 1 (P), Exhaust 3 (R) / 5 (S)	4 to 7	20
G 1/8 or NPT 1/8	Working ports 2 (B) / 4 (A), Pilot ports	3 to 6	7

Mechanical Stress on Solenoid

Never use the solenoid coil or pilot head as a lever arm when tightening pneumatic threaded fittings.

Pneumatic Installation and Hose Specifications

Pneumatic lines connecting to the bottom D8 push-in fittings must meet the following structural requirements:

• Minimum polymer hardness: 40 Shore D (tested per DIN 53505 or ISO 868).
• Outer diameter tolerances conforming to DIN 73378 (deviation within ±0.1 mm of nominal).
• Ends cut squarely at 90°, fully deburred, and free of scratches, cuts, or surface ovality.

Push-In Connector Tolerances (ISO 14743:2020)

Hose Material	Outer Diameter (OD) [mm]	Permissible OD Deviation [mm]
Polyamide (PA)	3 to 10	±0.08
Polyamide (PA)	12 to 16	±0.10
Polyurethane (PU)	3 to 8	±0.10
Polyurethane (PU)	10 to 16	±0.15

Minimum Retention Force for Pneumatic Tubing

Tubing inserted into push-in claws must withstand standard tensile loads per DIN ISO 14743:2020:

Metric OD [mm]	Fractional OD [in (mm)]	Minimum Tensile Force PA [N]	Minimum Tensile Force PU [N]
3	1/8 (3.17)	60	25
4	5/32 (4.00)	70	50
6	1/4 (6.35)	120	100
8	5/16 (8.00)	170	150
10	3/8 (9.52)	250	200
12	1/2 (12.70)	300	200
14	—	300	250
16	5/8 (16.00)	350	300

Tubing Retention with Soft Materials

When using flexible polyurethane (PU) tubing, install internal brass support sleeves (identification part ID 20099400) inside the hose end to preserve circular diameter and guarantee positive seal retention under alternating pressure.

Electrical Installation

BURKERT 20079750 utilizes discrete single wiring to individual coil sockets. Solenoids interface via standardized cable plugs conforming to DIN EN 175301-803 Form C (such as Type 2516).

Position the sealing gasket (1) evenly between the coil body and the cable plug (2). Fasten the central fixing screw with a maximum tightening torque of 0.3 Nm. When cable plugs are installed with appropriate seals on all 12 coils, verify continuity across the grounding contacts.

PE Test Parameter	Permissible Limit	Test Conditions
Protective conductor resistance	Maximum 0.1 Ω	Test current: 1 A, Test voltage: 12 V

Impulse Pilot Switching Logic

For impulse (bistable) solenoid versions, electrical control signals require correct polarity and a minimum pulse duration of 50 ms:

Terminal Configuration	Resulting Pilot State	Port State (Function G)	Port State (Function C)
(+) on pin 2 / (-) on pin 1	Pilot valve opens	1 connects to 2, 4 connects to 3	1 connects to 4
(+) on pin 1 / (-) on pin 2	Pilot valve closes	1 connects to 4, 2 connects to 3	4 connects to 3

Commissioning and Troubleshooting

Prior to energizing the valve manifold, perform the following verification steps:

1. Confirm supply pressure is between 2.0 and 10.0 bar, ensuring upstream filters and regulators deliver adequate continuous volume flow.
2. Confirm port 1 is connected to supply air and port 3 is connected to exhaust; never invert ports 1 and 3.
3. Return all manual overrides to their disengaged zero position (flush with housing).
4. Energize electrical control lines matching rated coil voltage within ±10% tolerance.

Fault Condition	Potential Root Cause	Corrective Action
Valve slices fail to actuate	Missing or insufficient electrical supply voltage	Verify supply wiring; confirm voltage meets nameplate value (tolerance ±10%).
	Manual override engaged in test lock position	Rotate manual override back to neutral disengaged zero position.
	Supply pressure below operating threshold	Restore main pressure to ≥ 2.0 bar; verify upstream regulators and shutoff valves deliver rated volume.
Delayed switching or blow-off at exhaust ports	Main line pressure drops during valve cycling	Install higher capacity supply line or accumulator; ensure pressure remains ≥ 2.0 bar during simultaneous switching.
	Block pressurized while valves were already energized	Pressurize manifold while solenoid coils remain in de-energized rest state.
	Excessive exhaust back-pressure	Clean clogged silencers or enlarge exhaust pipe diameter.
	Particulate contamination inside pilot or main spool	Blow out exhaust passages with pulsed air; replace contaminated pilot or valve slice.
Manifold block leakage between slices	Missing, misaligned, or pinched O-rings between modules	Disassemble sub-block, replace defective seals, and verify seating of 2 module O-rings.
	Damaged flat seal between valve slice and base plate	Inspect valve underside; replace damaged profile seal and retorque to 0.6 Nm.

Disassembly, Module Options, and Storage

1. De-energize electrical controls and fully exhaust compressed air from supply and working lines.
2. Loosen rail clamping screws by approximately 4 turns and lift the assembly upward off the standard DIN rail.
3. Insert a flat-blade screwdriver into the disassembly release slot on the front of the base module to unlatch the upper retention hook, then slide the sub-block module laterally.
4. To remove tubing from push-in fittings, depress the release collar squarely toward the fitting body and withdraw the hose line.

Right Connection Module Functions

The right connection module can serve as an auxiliary feed point for high-flow installations or partition internal supply galleries into independent pressure zones by piercing designated internal isolation walls.

Transport and Storage Specifications

• Store in dry, dust-free environments within a temperature range of -40 °C to +55 °C.
• Retain protective shipping plugs on all pneumatic ports and coil electrical pins until immediate field piping.
• Dispose of electronic assemblies, seals, and metal parts separately in compliance with regional environmental directives.