BURKERT 20121702 (Type 8640) is a 16-bank modular pneumatic valve island configured with a 33 mm station width, G 1/2 pressure supply ports, and G 1/4 working connections positioned opposite the supply side. Operating on a single-wiring electrical arrangement without internal fieldbus communication, the assembly utilizes 3/2-way valve functionality to control neutral gases and compressed air within a nominal operating pressure envelope of 2.00 bar to 8.00 bar.

Designed for integration onto standard DIN rails in control cabinets, this valve island integrates multiple sub-base modules into a centralized pneumatic distribution manifold. The pilot stages are operated by low-power solenoid pilot valves, while NBR seals and robust modular bodies ensure tight pneumatic isolation across medium operating temperatures from 0 °C to +50 °C.

Valve Island Architecture and Valve Design

The pneumatic block integrates modular sub-bases equipped with Type 5470 solenoid valves, driven by Type 6106 pilot valves. Each valve station features internal pilot channeling, diaphragm-seat seals, integrated working ports, and manual override mechanisms.

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
7	Cable plug Type 2506 / Type 2516

Manual Override Function

Manual operation allows commissioning and functional checks when electrical control signals are de-energized.

Operating the Manual Override

To activate the valve manually, press the manual override down and turn it 90° clockwise until it hits the mechanical stop. The override locks mechanically and does not reset automatically. Return it to the 0° zero position before initiating electrical operation.

Pneumatic Port Numbering

All pneumatic connections on the Type 8640 island and individual valve slices follow standard numeric markings:

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

Circuit Functions and Conversion

Depending on the internal configuration and base porting, Type 5470 valve slices support standard directional functions:

• Function C (3/2-way, normally closed): In rest position, pressure port 1 (P/NC) is closed; working port 2 (A/OUT) vents through exhaust port 3 (R/NO).
• Function D (3/2-way, normally open): In rest position, pressure port 1 (P/NO) communicates with working port 2 (B/OUT); exhaust port 3 (R/NC) is closed.
• Function G (4/2-way): In rest position, pressure port 1 (P) feeds working port 2 (A); working port 4 (B) discharges to exhaust port 3 (R).

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

A 4/2-way valve can be converted to 3/2-way functionality by closing one of the working ports with a dedicated threaded plug or stopper:

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

Technical Specifications

Parameter	Specification
Ident Number (Article Number)	20121702
Valve Island Type	8640
Number of Valve Stations	16-bank
Station Width (Add-on dimension 1)	33 mm
Valve Function	3/2-way
Pressure Port 1 (P)	G 1/2
Working Ports 2 (B) / 4 (A)	G 1/4
Nominal Operating Pressure Range	2.00 bar to 8.00 bar
Pilot Pressure Requirement	2 bar to 10 bar (at least 70% of operating pressure)
Minimum Pressure Differential (Port 1 to 3)	2 bar
Medium Temperature Range	0 °C to +50 °C (operation below 0 °C restricted to dried air)
Ambient Temperature Range	0 °C to +55 °C
Medium	Filtered compressed air (particle size max. 10 μm, lubricated or unlubricated); neutral gases (5 μm filtering)
Seal Material	NBR
Protection Class	IP20 (base unit configuration); IP65 with Type 2516 cable plug correctly fitted
Mounting Standard	DIN-rail installation (EN 50022: 35 x 15 or 35 x 7.5)
Voltage Tolerance	±10%
Coil Power Rating	2 W (standard continuous DC coil)
Approvals	UL Recognized cURus (pneumatic valves)

Continuous Operation Guideline

If continuous operation is interrupted, perform a minimum of 1 to 2 switching operations per day throughout the downtime to maintain functional switching reliability.

Modular Block Assembly and Mounting

Type 8640 valve blocks are assembled modularly by snapping base modules together between dedicated left and right connection modules.

Item	Designation
1	Left connection module
2	Latch tab
3	Latch hook
4	Base modules (3-fold)
5	Right connection module
6	Base modules (2-fold)
7	Exhaust channel 3 (R)
8	Supply channel 1 (P)
9	Inter-module O-ring

Assembly Sequence and Torques

1. Begin block assembly starting from the left connection module.
2. Ensure each module interface is equipped with 2 O-rings. Lightly oil or grease all O-rings prior to latching.
3. Engage the lower latch hooks of the adjoining module into the latch grooves of the preceding unit.
4. Pivot the module slightly upward until the upper latch hook snaps securely into place.
5. Fit 3 O-rings into the rear sealing recesses of each Type 5470 valve slice.
6. Mount each valve body to the base block using two fastening screws. Tighten with a torque of 0.6 ±0.1 Nm.

Sealing Integrity

Crushed, twisted, or missing O-rings and profile seals between modular sub-bases will result in pneumatic leakage across the central channels.

Island Mounting Options

• Standard DIN Rail Installation: Hook the top groove of the valve island onto the standard rail (EN 50022, 35 x 15 mm or 35 x 7.5 mm). Snap the bottom clamping elements onto the rail and tighten the clamp fixing screws.
• Wall Mounting: Fasten the island connection flanges directly to the mounting panel using M4 screws.

Port Thread Size	Function / Location	Recommended Torque [Nm]	Maximum Torque [Nm]
G 1/4 / NPT 1/4	P (Supply), R/S (Exhaust) connections	4 to 7	20
G 1/8 / NPT 1/8	P, R/S connections, A/B working ports	3 to 6	7

Pneumatic Installation and Hose Line Guidelines

Pressure Hazard

Depressurize and vent all pneumatic lines before commencing installation or servicing. Loose, flapping compressed air lines can cause severe bodily injury.

When connecting pneumatic lines to push-in connectors or threaded ports, adhere to the following hose line criteria:

• Material Hardness: Minimum 40 Shore D in accordance with DIN 53505 / ISO 868.
• Outer Diameter: Conforming to DIN 73378 with a maximum tolerance deviation of ±0.1 mm from nominal size.
• Preparation: Cut hose ends cleanly at a 90° right angle; ensure the outer circumference is free from burrs, scratches, or oval distortion.

Hose Outer Diameter Tolerances (ISO 14743:2020)

Hose Material	Hose OD [mm]	Permitted Deviation OD [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 Push-In Fittings

Pneumatic push-in fittings must withstand the tensile testing values specified in DIN ISO 14743:2020 without detaching:

Hose OD [mm]	Hose OD [in]	Min. Tensile Force PA [N]	Min. 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

Hose Support Sleeves

When using softer polyurethane (PU) tubing under high operating temperatures or dynamic movements, install internal support sleeves (ID 20099400) to prevent hose collapse and maintain sealing grip.

Electrical Installation

Each solenoid valve station on the single-wired 20121702 island utilizes an industrial standard Form C connection interface.

• Cable Plug Compatibility: Type 2516 or approved connectors according to DIN ISO 175301-803 Form C.
• Fastening Torque: Tighten the central cable plug screw with a maximum torque of 0.3 Nm (1.0 Nm maximum for coil contact retention).
• Protective Conductor Verification: Ensure continuous grounding continuity between the coil protective earth contact and the valve body.

Test Parameter	Required Test Value
Earth Contact Resistance	Maximum 0.1 Ω
Test Voltage	12 V
Test Current	1 A

Impulse Solenoid Control Truth Table

For bistable impulse coil variants, observe correct wiring polarity and provide a minimum pulse duration of 50 ms:

Plug Terminal Configuration	Pilot Valve State	Function WWG Flow Path	Function WWC Flow Path
(+) on pin 2, (-) on pin 1	Pilot valve opened	1 → 3, 2 → 3	1 → 4
(+) on pin 1, (-) on pin 2	Pilot valve closed	1 → 2, 4 → 3	4 → 3

Troubleshooting and Fault Clearance

Fault Symptom	Probable Cause	Corrective Action
Valves do not switch	Operating voltage missing or below tolerance	Check wiring terminals; verify voltage corresponds to the rating on the type label.
Valves do not switch	Manual override engaged	Reset manual override to the zero position.
Valves do not switch	Insufficient supply pressure	Ensure operating pressure is at least 2 bar; check upstream pressure regulators and filters.
Valves switch with delay or exhaust continuously	Inadequate air volume or pressure drop	Size air supply lines adequately; verify minimum 2 bar operating pressure.
Valves switch with delay or exhaust continuously	Valve not in home position during pressure buildup	Apply supply pressure to the valve block before switching electrical controls.
Valves switch with delay or exhaust continuously	Exhaust back-pressure from clogged or undersized silencers	Clean contaminated silencers or install higher-flow silencers and expansion vessels.
Valves switch with delay or exhaust continuously	Contamination in pilot or main valve seat	Apply pressure pulses through exhaust ducts to dislodge dirt, or replace affected valve slice.
Pneumatic leaks on valve island	Damaged or missing O-rings between sub-bases	Inspect module joints; replace damaged or omitted inter-base O-rings.
Pneumatic leaks on valve island	Misaligned flat seal under valve body	Realign or replace flat gasket between valve body and sub-base.

Disassembly and Auxiliary Feeding

1. Disconnect all electrical connectors and depressurize the pneumatic system.
2. To release push-in tubing, depress the release collar fully while pulling the hose straight out.
3. Loosen the rail clamping screws approximately 4 turns and lift the assembly off the DIN rail.
4. To separate individual sub-base modules, insert a flat screwdriver into the disassembly notch on the front edge to release the upper latch hook, then slide the module sideways.

Dual Pressure and Auxiliary Air Feeding

The right connection module can be utilized in specialized layouts as an intermediate pressure separator, allowing two distinct operating pressure zones on a single island, or as an auxiliary air inlet for high-flow installations. If required, pierce the pre-punched lateral knockout ports on channels 1 and 3.