

BURKERT 312685 is a Type 6213 EV servo-assisted 2/2-way normally closed solenoid valve with stainless steel body, DN 10 orifice, NPT 1/4 port, EPDM seal, and 24 V DC operation across 0 to 10 bar.

BURKERT 312685 (Type 6213 EV) is a servo-assisted 2/2-way solenoid valve designed for neutral liquids and compatible gases. The valve operates with circuit function A (normally closed in de-energized state). Equipped with a spring-coupled diaphragm system, the valve opens reliably without requiring a minimum differential pressure across the inlet and outlet ports, covering an operating pressure range from 0 to 10 bar. Construction features a cast stainless steel 1.4408 body, an internal NPT 1/4 process connection, an orifice size of DN 10 mm (3/8"), and durable EPDM internal and external sealing.

The unit is actuated by a 24 V DC solenoid coil operating with Class H thermal insulation. With a calibrated water flow coefficient (Kv) of 1.3 m³/h and a nominal air flow rate (QNn) of 1,400 l/min, the valve combines high volumetric throughput with an installation face-to-face length of 50 mm. The assembly is rated IP65 and NEMA 4X when paired with an approved DIN EN 175301-803 Form A cable plug, and carries cURus component certification according to UL 429 for electrically operated valves.
Zero Differential Pressure Operation
The spring coupling between the plunger and the diaphragm assists the opening process directly from 0 bar differential pressure, eliminating the stalling risks common to purely differential pressure-driven pilot valves.
| Parameter | Value |
|---|---|
| Type / Generation | Type 6213 / Generation EV |
| Article Number | 312685 |
| Circuit Function | CF A (2/2-way, normally closed) |
| Nominal Diameter (DN) | 10 mm (3/8") |
| Pilot Control Orifice | 1.2 mm |
| Port Connection 1 | NPT 1/4 internal thread |
| Operating Pressure Range | 0.00 to 10.00 bar (liquid) |
| Nominal Pressure Rating | PN 10 (DIN EN 1333) |
| Flow Coefficient Kv (Water) | 1.3 m³/h |
| Nominal Flow QNn (Gas) | 1,400 l/min |
| Operating Voltage | 24 V DC (tolerance ±10%) |
| Duty Cycle | 100% continuous operation (ED) |
| Power Consumption | Cold: 11 W; Warm: 10 W |
| Switching Time (DN 10) | Opening: 10–100 ms; Closing: 100–200 ms |
| Medium Temperature | -30 °C to +100 °C |
| Ambient Temperature | -30 °C to +55 °C |
| Permissible Fluid Viscosity | Max. 21 mm²/s |
| Enclosure Protection | IP65 (with cable plug), NEMA 4X |
| Approval Standard | cURus Recognized, UR Component (UL 429) |

| Item No. | Component | Material Specification |
|---|---|---|
| 1 | Nut | Stainless steel 1.4305, PTFE-coated / Thick-film passivated steel (RoHS compliant) |
| 2 | Coil | Epoxy (insulation class H) / Polyamide |
| 3 | Stopper | Stainless steel 1.4113 |
| 4 | Shading Ring | Not applicable (DC version; silver Ag on AC stainless models) |
| 5 | Magnetic Plunger (Core) | Stainless steel 1.4113 |
| 6 | O-ring | FKM |
| 7 | Plunger Seal | EPDM |
| 8 | Bonnet | Polyamide (PA6) |
| 9 | Cover | Stainless steel 1.4301 (for DN 10–DN 25) |
| 10 | Spring | Stainless steel 1.4310 |
| 11 | Diaphragm | EPDM |
| 12 | Diaphragm Support | PPS GF40 reinforced with stainless steel components |
| 13 | Valve Body | Stainless steel 1.4408 (CF8M) |

Dimensions below correspond to standard DN 10 threaded variants with stainless steel bodies:
| DN | Height A (mm) | Height B (mm) | Coil Width C (mm) | Coil Depth D (mm) | Center-to-Port E (mm) | NPT Thread Depth F2 (mm) | Port Thread G2 | Overall Length L (mm) | Hex Wrench Size SW (mm) | Coil Size |
|---|---|---|---|---|---|---|---|---|---|---|
| 10 | 71.1 | 82.1 | 36 | 46 | 22 | 10.0 | NPT 1/4 | 50 | 22 | Size 6 (40 mm) |

| Coil Size | Width H (mm) | Depth J (mm) | Length K (mm) | Distance O (mm) | Bore Diameter M (mm) |
|---|---|---|---|---|---|
| 5 | 32 | 20.5 | 45 | 41 | 3.4 |
| 6 | 40 | 23.5 | 51 | 41 | 3.4 |
Operating coil Size 6 (40 mm width) draws an initial cold active power of 11 W and a warm stabilized power of 10 W on 24 V DC. The solenoid actuator is rated for continuous 100% ED duty cycle operation.

Electrical and Pressure Hazards
Connecting the cable plug:
Upstream Filtration
To prevent particulate contamination from obstructing the pilot control orifice (1.2 mm) or the diaphragm relief holes, install an upstream dirt trap or strainer with a mesh rating of ≤ 500 µm.

Fire and Overheating Hazard
Never energize the solenoid coil when it is removed from the valve core guide tube. Operating the coil without the valve body and magnetic armature causes rapid inductive overheating, resulting in permanent coil destruction and fire risks.
| Solenoid Type | Solenoid Width | Tightening Torque |
|---|---|---|
| AC10 (Coil Size 5 or 6) | 32 mm or 40 mm | 5 Nm |
| AC19 (Coil Size K) | 42 mm | 10 Nm |
| Symptom | Probable Cause | Corrective Action |
|---|---|---|
| Valve fails to actuate | Power supply disconnected or incorrect voltage | Check 24 V DC voltage and verify type label compliance |
| Solenoid coil winding interrupted or short-circuited | Inspect coil continuity; replace coil assembly if open | |
| Core or plunger guide tube fouled with particulate | Disassemble actuator core area and clean internal surfaces | |
| Operating pressure exceeds maximum threshold (> 10 bar) | Check system line pressure and adjust within 0–10 bar | |
| Valve fails to close | Diaphragm control bore obstructed by debris | Disassemble valve cover; clean pilot channel and diaphragm bore |
| Internal components contaminated or mechanically stuck | Flush body cavity and verify free movement of plunger and spring | |
| Fluid leaks through body joint | Fasteners insufficiently torqued or seal misaligned | Check cover bolt torques and replace deformed EPDM seals |
| Accessory Type | Description / Specification | Ordering Number |
|---|---|---|
| Type 2518 Cable Plug | Form A DIN EN 175301-803, without circuitry, 0–250 V AC/DC | 314802 |
| Type 2518 Cable Plug | Form A DIN EN 175301-803, with LED indicator, 12–24 V AC/DC | 314812 |
| Type 2518 Cable Plug | Form A DIN EN 175301-803, with LED and varistor overvoltage protection, 12–24 V AC/DC | 314820 |
| Type 2509 Cable Plug | Form A DIN EN 175301-803, unshielded standard, UL 429 and ATEX Cat. 3 GD compliant | 137943 |
| Type 1087 Plug-on Timer | Form A DIN EN 175301-803, analogue timer unit, 10–30 V AC/DC, cURus certified | 348906 |
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