BURKERT 703301 (Type 8640) is a modular pneumatic valve island configured with 11 valve stations on a 19 mm grid width. Engineered for centralized pneumatic control in process automation, this assembly combines Type 5470 pneumatic directional valves with integrated Type 6106 pilot valves. The assembly provides G 1/4 supply ports, D6 push-in working connections positioned at the bottom of the block, and electrical actuation through a Sub-D 25-pin multi-pole interface. It operates within a nominal pressure range of 2.0 to 8.0 bar and delivers an IP54 degree of protection when installed with matching connectors.

Design and Functional Architecture

The Type 8640 pneumatic system integrates modular base rails (Type MP05) with Type 5470 directional control valves. Each valve station incorporates a Type 6106 3/2-way pilot valve mounted on a valve body containing seat seals, diaphragm elements, and internal switching pathways. Fluid supply and exhaust are routed through centralized manifold galleries, while working air is directed through dedicated service ports.

Item	Designation	Function
1	Pilot valve Type 6106	3/2-way solenoid actuator controlling pilot stage
2	Exhaust port 3	Common vent connection for de-actuation air
3	Pressure port 1	Main pneumatic supply channel
4	Working port 4	Pneumatic output channel A
5	Working port 2	Pneumatic output channel B
6	Manual override	Mechanical testing switch
7	Cable plug Type 2506 / connector	Electrical command interface

Port Numbering Convention

Pneumatic connections follow standardized numbering across the block:

• Port 1 (P): Primary pressure supply channel.
• Ports 2 and 4 (B and A): Working ports connected to pneumatic actuators.
• Port 3 (R): Exhaust channel for vented media.

Manual Override Operation

Each valve station is equipped with a mechanical override switch to facilitate setup and functional testing without electrical power.

To actuate the valve manually, press the manual override pin and rotate it 90° clockwise until it hits the internal mechanical stop. The override locks in position and will not return automatically. To reset, turn the pin 90° counterclockwise back to its zero position.

Manual Override Safety

Operate the manual override only when the electrical power is disconnected. Ensure the manual override is completely returned to its neutral zero position before initiating normal electrical operation.

Circuit Functions and Conversion

Type 5470 valves support multiple flow path configurations, including 3/2-way and 4/2-way operation:

• Circuit Function C (3/2-way): In rest position, pressure port 1 (P/NC) is closed, and working port 2 (A/OUT) is exhausted through port 3 (R/NO).
• Circuit Function D (3/2-way): In rest position, pressure port 1 (P/NO) feeds working port 2 (B/OUT), while exhaust port 3 (R/NC) remains closed.
• Circuit Function G (4/2-way): In rest position, pressure port 1 (P) connects to working port 2 (A), and working port 4 (B) vents through port 3 (R).

Converting 4/2-Way to 3/2-Way Operation

A standard 4/2-way valve station can be reconfigured into a 3/2-way function by inserting a dedicated blind plug into one of the working outlets.

Port 2 Status	Port 4 Status	Resulting Circuit Function
Closed (with stopper)	Open	Function C (Normally Closed)
Open	Closed (with stopper)	Function D (Normally Open)

Technical Data and Operating Limits

BURKERT 703301 complies with relevant EU harmonisation legislation and technical standards. Operating conditions must be maintained within the following parameters:

Parameter	Specified Value
Nominal Operating Pressure Range	2.0 bar to 8.0 bar
Pilot Pressure Range	2.0 bar to 10.0 bar (must be at least 70% of operating pressure)
Required Pressure Differential	Minimum 2 bar difference between port 1 and port 3
Medium Temperature	0 °C to +50 °C (operation restricted to dried air below 0 °C)
Ambient Temperature	0 °C to +55 °C
Storage Temperature	-40 °C to +55 °C
Operating Fluid	Filtered compressed air (particle size ≤ 10 µm), neutral gases (≤ 5 µm filtering)
Lubrication Condition	Unlubricated preferred; lubricated air permissible
Seal Material	NBR
Voltage Tolerance	±10%
Degree of Protection	IP54 (with properly installed Sub-D connector)

Continuous Operation Cycling

To preserve functional switching reliability during extended periods of continuous energization or standby downtime, actuate each valve station 1 to 2 times per day.

Electrostatic Discharge (ESD) Protection

The internal control modules contain electronic components sensitive to electrostatic discharge. Follow EN 61340-5-1 handling protocols. Never touch conductive pins or circuit traces while supply voltage is active.

Mechanical Assembly and Installation

Modular Block Assembly

The valve block assembly consists of a left supply module, intermediate multi-station base segments (2-fold and 3-fold), individual valve units, and a right terminating module.

Item	Component Description
1	Left connection module
2	Module latch tab
3	Module latch hook
4	Base module (3-fold)
5	Right connection module
6	Base module (2-fold)
7	Common exhaust channel 3 (R)
8	Common supply channel 1 (P)
9	Inter-module sealing O-rings

Assembly procedure for modular blocks:

1. Begin the mechanical buildup from the left connection module.
2. Ensure two O-rings are present and undamaged on each inter-module joint. Lightly lubricate the O-rings with grease or oil prior to latching.
3. Hook the lower latch hooks of the adjacent module into the mating grooves of the preceding block.
4. Pivot the module upward slightly until the upper latch hooks lock securely in place.
5. Fit 3 O-rings into the dedicated recesses on the rear mounting interface of each Type 5470 valve.
6. Mount each valve body onto the base module using two screws. Tighten with a torque of 0.6 ±0.1 Nm. Crushed or displaced profile seals will result in pneumatic leakage.

Mounting onto Standard Rail or Flat Surface

The complete 11-bank assembly can be mounted onto DIN rails or bolted directly to machine frames.

• DIN-Rail Installation: Compatible with standard rail EN 50022 (35 x 7.5 mm or 35 x 15 mm). Engage the upper groove of the manifold block onto the DIN rail, snap the lower clamping brackets into position, and tighten the bracket clamping screws.
• Wall / Panel Mounting: Secure the block directly against a flat mounting plate through the integrated mounting flanges using M4 fasteners.

Single Valve Direct Mounting

When individual Type 5470 valve units are decoupled or installed standalone, secure them via direct M4 fastening holes.

Solenoid Coil 180° Rotation

If installation constraints require cable entry from the opposite direction, the pilot valve coil can be rotated 180°:

1. Loosen the M2 retaining screw and withdraw the coil assembly from the valve body.
2. Rotate the coil 180° and reposition it onto the body interface.
3. Fasten the M2 screw in two progressive torque stages:
   • Stage 1: Tighten to 0.1 Nm (±0.05 Nm).
   • Stage 2: Finalize torque to 0.2 Nm (±0.05 Nm).
4. Verify that the protective grounding contact between the coil and valve body is fully seated.

Pneumatic Connection Tightening Torques

Adhere strictly to the recommended torque limits when connecting rigid or threaded fittings into the aluminum and polymer ports:

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

Pneumatic Installation and Tubing Requirements

Working ports on Article 703301 are engineered as D6 push-in connectors positioned on the valve bottom. Main supply and exhaust ports utilize G 1/4 female threads.

Piping Preparation

Flush and purge all supply pipes prior to connection to remove manufacturing debris and metal shavings. Install an upstream dirt trap or filter regulator rated at ≤ 5 µm. Never use a solenoid coil as a lever arm when tightening threaded fittings.

Pneumatic hose lines must satisfy the following technical parameters:

• Hose Hardness: Minimum 40 Shore D in compliance with DIN 53505 / ISO 868.
• Outer Diameter: Conforming to DIN 73378 (maximum permissible outer diameter deviation: ±0.1 mm from nominal size).
• Preparation: Tubing must be cut perpendicular to the centerline, deburred, and free of outer surface scratching or flattening.

Push-in Connector Tubing Tolerances (ISO 14743:2020)

Material	Hose Outer Diameter (mm)	Permitted 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 Tensile Force for Pneumatic Tubing

Push-in connections must withstand the standardized tensile proof forces listed below without disengaging or venting leaks:

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

Flexible Hose Retention

When using softer polyurethane (PU) tubing subject to mechanical movement or vibration, install internal support sleeves (Ident 20099400) inside the hose end to maximize retention and prevent seal distortion.

Electrical Installation

Article 703301 utilizes a centralized multi-pole Sub-D 25-pin connection. Individual valve plug connections follow DIN EN 175301-803 Form C specifications (such as Type 2516).

• Fastening Torque: Tighten cable plug center fastening screws to a maximum of 0.3 Nm (maximum 1.0 Nm on Type 2516 coil contacts).
• Protective Conductor Verification: Ensure electrical continuity between the earth terminal and the valve body. Grounding resistance must measure ≤ 0.1 Ω at a test condition of 12 V and 1 A.

Impulse Solenoid Control Logic

For bistable or pulse-driven pilot coils, adhere to the polarity switching logic below. Pulse duration must be at least 50 ms.

Electrical Pin Configuration	Pilot Stage State	Resulting Port Pathway (Function G)	Resulting Port Pathway (Function C)
(+) on pin 2 / (-) on pin 1	Pilot valve energized open	1 to 3, 2 to 3	1 to 4
(+) on pin 1 / (-) on pin 2	Pilot valve de-energized closed	1 to 2, 4 to 3	4 to 3

Troubleshooting and Fault Rectification

Fault Symptom	Probable Root Cause	Corrective Action
Valves fail to switch	No supply voltage or operating voltage below tolerance	Verify power circuit wiring and ensure voltage matches nameplate ratings (24 V DC ±10%).
	Manual override locked in non-zero position	Reset manual override detent back to neutral zero position.
	Supply pressure insufficient (< 2 bar)	Establish pressure supply above 2.0 bar minimum threshold. Verify supply lines and upstream regulators.
Valves switch sluggishly or vent continuously through exhaust	Operating pressure supply volume inadequate	Ensure volume capacity is sufficient across all upstream filters, regulators, and shut-off valves.
	System pressurized while valves were in energized position	Ensure pilot valves are de-energized (home position) during initial pneumatic pressurization.
	Exhaust backpressure due to clogged or undersized silencers	Clean contaminated silencer inserts or install larger exhaust mufflers / expansion vessels.
	Contamination or particulates inside pilot valve mechanism	Apply rapid pressure pulses through exhaust galleries to clear debris, or replace the pilot valve capsule.
External leakage between manifold modules	Missing, pinched, or damaged inter-module O-rings	Disassemble module junction, inspect seal seats, and replace damaged O-rings.
	Displaced flat gasket between valve body and sub-base	Re-seat the interface gasket or replace with a new seal, tightening valve screws to 0.6 ±0.1 Nm.

Disassembly and Decommissioning

1. Disconnect all electrical control lines and multi-pole Sub-D connectors.
2. Depressurize the pneumatic system completely and vent all upstream air reservoirs.
3. Tubing Disconnection: Depress the outer release collar of the D6 push-in fitting squarely and withdraw the pneumatic tubing.
4. Manifold Block Removal: Loosen the rail clamping bracket screws (approximately 4 turns) and tilt the assembly upward off the DIN rail.
5. Module Separation: Insert a flat-blade screwdriver into the disassembly notch on the front edge to release the upper latch hook, then disengage the base module laterally.
6. Store components within a clean, dry environment at -40 °C to +55 °C with port plugs installed.