BURKERT 388757 (Type 3361) is an electromotive 2-way globe control valve engineered for demanding process automation. Equipped with a stainless steel body, G 1/2 internal thread connection (DN 15), and an 8 mm (5/16") seat diameter, fluid flows in below the seat to ensure stable throttling control. The electromotive linear actuator generates 1300 N driving force (AG2) on a 24 V DC power supply, delivering a typical closing time of 3,400 ms. The stainless steel control cone provides an equal percentage 50:1 flow characteristic with a rated water Kv of 2.1 m³/h (Cv 2.4 gpm). Operating pressures range from 0 to 25 bar (PN 25 / Class 150), and process media temperatures extend from -10 °C to +185 °C.

Positioning and process control functionality are governed by integrated digital electronics featuring an illuminated display with pushbuttons, Service-büS communication, and comprehensive I/O (1 analogue input, 1 digital input, 1 process value input, 1 analogue output, and 2 digital outputs). The actuator housing is constructed from powder-coated aluminium and polyphenylene sulphide (PPS), sealed to IP65/IP67 and NEMA 4X. A factory-installed SAFEPOS energy pack provides internal electrical storage, automatically closing the valve if main electrical power is interrupted.

Technical Data

Attribute	Technical Specification
Valve Type / Model	Type 3361 / Article 388757
Flow Construction	2-way globe valve, flow below seat
Nominal Port Diameter	G 1/2 internal thread (DN 15)
Seat Diameter / Orifice	8 mm (5/16")
Flow Capacity	Kv 2.1 m³/h (water) / Cv 2.4 gpm
Control Characteristic	Equal percentage 50:1
Operating Pressure Range	0.00 bar to 25.00 bar (PN 25 / Class 150)
Medium Temperature Range	-10 °C to +185 °C
Operating Ambient Temperature	-25 °C min. (Storage: -40 °C to +70 °C)
Supply Voltage	24 V DC
Actuator Size / Force	AG2 (1300 N electromotive thrust)
Typical Closing Time	3,400 ms
Control Function	Normally closed (NC), electrical energy storage
Materials	Body: Stainless steel; Seat seal: Stainless steel; Actuator: Powder-coated aluminium / PPS
Protection Rating	IP65 / IP67, NEMA 4X
Regulatory Conformity	Food (EC) 1935/2004 compliant

Spare Parts and Ordering Numbers

Original replacement parts preserve the calibration and sealing geometry of the Type 3361 globe valve body. The replacement sets for Type 3361 include control cone sets, valve seat sets, packing gland seal sets, and spindle guides.

Component Description	Model Specifics (DN 15 / Seat 8)	Order Number
Control cone set (steel/steel)	Seat size 8, Orifice DN 10/15 (includes cone, dowel pin, graphite seal)	149 935
Valve seat set	Seat size 8, Orifice DN 10/15 (includes valve seat, graphite seal)	262 147
Packing gland seal set	Spindle ø10 mm, DN 15–DN 20	285 685
VA spindle guide for packing gland	Spindle ø10 mm, Body DN 15	246 577
SAFEPOS energy-pack	Replacement emergency power pack	285 834
Plastic display module	Replacement HMI module	277 869
Plastic dummy cover	Actuator top cover without display	277 881
Installation tool for valve seat	Seat replacement tool DN 15	652 604
Modified socket wrench for packing gland	Spindle ø10 mm, DN 15 (Wrench size SW19)	683 220
Pipe connection holding device	Body clamping tool DN 15–DN 20	693 770

Operating State and Manual Override

Type 3361 operates in either AUTOMATIC or MANUAL mode. Setting the operating state depends on the device hardware configuration:

• Devices with display module: Hold down the back key to navigate to View 1 (home screen). Open the context menu by holding down the menu key and select the MANU / AUTO layout. Briefly press the menu key to toggle states. In MANUAL mode, the HAND symbol appears on the top information bar alongside open and closed directional arrows, and the LED illuminated ring flashes. Press the upper navigation key to drive the valve open or the lower navigation key to drive it closed.
• Devices without display module: Rotate the dummy cover counter-clockwise to remove it. Locate DIP switch 4: set to ON (upwards) for MANUAL mode, or downwards for AUTOMATIC mode. Use the internal OPEN and CLOSE pushbuttons located below the DIP switches to electrically position the valve stem while observing the mechanical position indicator.

When electrical power is unavailable, manual positioning must be performed mechanically:

Mechanical Override Limitations

The mechanical manual override may be operated only in a de-energised state. Exceeding the maximum tightening torque of 2 Nm at the valve end positions will cause mechanical failure of the override assembly.

1. Switch off supply voltage and confirm that the LED illuminated ring has extinguished.
2. Rotate the dummy cover or display module counter-clockwise and remove it (disconnect the HMI ribbon cable if equipped).
3. If a fieldbus gateway is present, unscrew its M3 socket head screw, rotate counter-clockwise, and disconnect its internal cable.
4. Insert a 3 mm Allen key into the mechanical override receptacle. Apply gentle downward pressure to couple the mechanism, turning counter-clockwise to open the valve stem or clockwise to close it.
5. Verify valve stem position via the mechanical indicator window, then remove the Allen key before restoring electrical power.

Actuator Removal and Installation

Pressure and Crush Hazard

Before opening fluid lines or detaching the actuator, depressurise and drain the pipeline. For actuators equipped with the SAFEPOS energy pack, wait until the internal capacitors discharge completely and the LED ring turns off.

Valve Position During Disassembly

The valve must be driven to at least 1/3 open before unscrewing the actuator from the valve body. Attempting to unscrew the actuator while the control cone is seated against the valve seat will permanently damage the seat contour and spindle assembly.

1. Set operating mode to MANUAL and drive the actuator to at least 1/3 open.
2. Disconnect 24 V DC power and confirm the LED ring turns off.
3. Secure the valve body in holding device 693770.
4. Apply an open-end wrench to the body connection hexagon flats and unscrew the actuator from the valve body.
5. Discard the spent graphite gasket.

When remounting the actuator onto the valve body, fit a new graphite seal (Figure 21) and lubricate the body connection external threads with Klüberpaste UH1 96-402 (or an oxygen-approved grease where applicable). Tighten the body connection using a calibrated torque wrench:

Body Connection Size	Tightening Torque (Nm)	Tightening Torque (lbf·ft)
DN 10 / DN 15 (G 1/2)	45 ±3 Nm	33 ±2 lbf·ft
DN 20	50 ±3 Nm	37 ±2 lbf·ft
DN 25	60 ±3 Nm	44 ±2 lbf·ft
DN 32 / DN 40	65 ±3 Nm	48 ±2 lbf·ft
DN 50	70 ±3 Nm	52 ±2 lbf·ft

Control Cone and Valve Seat Maintenance

Servicing the throttling trim requires the actuator to be separated from the body with the valve driven at least 1/3 open in MANUAL mode.

Replacing the Control Cone

1. Rest the cylindrical section of the control cone on a support prism to isolate the spindle from lateral impact.
2. Drive out the dowel pin using a 4 mm pin punch (for spindle ø10 mm, DN 10/15).
3. Remove the worn control cone.
4. Position new control cone 149 935 onto the spindle, aligning the pin through-holes.
5. Drive the replacement dowel pin in with a hammer until it is positioned symmetrically in the centre of the spindle axis.

Replacing the Valve Seat

1. Screw the size-specific tool insert for DN 15 into installation tool 652604.
2. Engage the tool in the valve seat notches and unscrew the valve seat counter-clockwise using a wrench.
3. Clean the internal body threads and sealing face thoroughly with dry compressed air.
4. Place new valve seat 262 147 onto the installation tool and grease its external threads with Klüberpaste UH1 96-402.
5. Screw the seat into the valve body by hand, then tighten using a torque wrench to the specified value:

Seat Size	Valve Body Connection	Coated Seats Torque (Nm)	Tolerance (Nm)
Seat 3 – 15 (Seat 8)	DN 10 / DN 15	20 Nm	+3 Nm
Seat 20	DN 20	28 Nm	+3 Nm
Seat 25	DN 25	40 Nm	+5 Nm
Seat 32	DN 32	65 Nm	+5 Nm
Seat 40	DN 40	85 Nm	+8 Nm
Seat 50	DN 50	120 Nm	+8 Nm

Packing Gland Seal Replacement

On DN 10 to DN 15 valves (seat sizes 3 to 10), the packing gland is accessible after separating the actuator base from the main actuator housing.

1. With the control cone removed, clamp the actuator base into a holding fixture.
2. Loosen the 4 base fastening screws and detach the actuator housing from the base.
3. Unscrew the lower spindle guide.
4. Carefully press the packing gland package out from the bore using a blunt tool, taking care not to score or scratch the upper spindle guide surface.

5. Lubricate the chevron seals of replacement seal set 285685 using the supplied Klüberpaste UH1 96-402.
6. Insert the individual components of the packing gland in the exact order shown in Figure 5.
7. Grease the spindle guide thread and screw it into the actuator base. For spindle ø10 mm (DN 10/15), tighten to 15 Nm.
8. Reassemble the actuator base to the housing and tighten the 4 base screws crosswise to 5 Nm.

Spindle Diameter	Valve Connection Size	Spindle Guide Tightening Torque
ø10 mm	DN 10 / DN 15	15 Nm
ø10 mm	DN 20	25 Nm
ø14 mm	DN 25	25 Nm
ø14 mm	DN 32 to DN 50	60 Nm

Position Controller Calibration (X.TUNE)

Uncontrolled Actuation Risk

Never run the X.TUNE calibration function while the valve is under process media pressure. Calibrating against line pressure causes incorrect stroke reference points, leading to improper shutoff and uncontrolled process deviations.

The automatic X.TUNE calibration routine adapts the position controller to the mechanical end stops and stroke travel of the newly installed seat and cone trim.

• Running X.TUNE via device pushbuttons: Remove the dummy cover. Simultaneously press and hold the OPEN and CLOSE pushbuttons for 5 seconds. The illuminated ring lights up orange while X.TUNE executes and returns to normal operating indication once completed.
• Running X.TUNE via display or Bürkert Communicator: Navigate to CONFIGURATION → Position Controller → MAINTENANCE → CALIBRATION → X.TUNE. Confirm the installed seat seal material, then select start.

Cancellation Message	Cause / Corrective Action
There are device errors.	An active system fault is preventing the calibration routine from starting.
Time limit exceeded	Mechanical movement exceeded maximum allowed run time. Inspect spindle for binding.
Motor current is too high.	Actuator encountered excessive mechanical resistance during stroke travel.
Lower end position not detected.	Position sensor failed to detect the closed seat contact limit. Check cone seating.

SAFEPOS Energy-Pack Replacement

The SAFEPOS energy-pack (part number 285834) provides emergency fail-close capability when power fails.

1. Isolate the 24 V DC power supply. Wait until the LED ring extinguishes completely, verifying the energy pack has discharged.
2. Remove the display module or dummy cover.
3. For devices without fieldbus gateway: Unscrew the two T20 screws and remove the LED/storage module. Loosen the 4 captive T25 screws on the actuator cover and lift the cover off.
4. For devices with fieldbus gateway: Unscrew the 3 mm Allen fastening screw, rotate the gateway counter-clockwise, disconnect the cable, remove the two T20 screws from the bayonet adapter, and lift the cover and adapter off together.
5. Loosen the T10 Torx locking screw on the SAFEPOS bracket. Slide the energy pack straight out along its guide tracks.
6. Slide the replacement pack fully into the guiding grooves, and tighten the T10 locking screw to 1.1 Nm.
7. Reinstall the actuator cover, tightening the T25 screws crosswise to 5 Nm. Reattach modules and torque T20 screws to 1.1 Nm.

Accessories

Item	Description / Configuration	Order Number
Operating Voltage Cable	M12 socket, 4-pole, length 5 m	918 038
I/O Signal Cable	M12 socket, 8-pole, length 2 m	919 061
Process Value Cable	M12 circular plug, 5-pole, length 2 m	559 177
USB büS Interface Set 1	büS stick set 1 (power supply, stick, terminating resistor, Y-distributor, 0.7 m M12)	772 426
USB büS Interface Set 2	büS stick set 2 (stick, terminating resistor, Y-distributor, 0.7 m M12)	772 551
büS Micro USB Adapter	M12 to büS Service interface micro USB	773 254
büS Extension Cable 1 m	M12 plug to M12 socket, 1 m length	772 404
büS Extension Cable 3 m	M12 plug to M12 socket, 3 m length	772 405
büS Extension Cable 5 m	M12 plug to M12 socket, 5 m length	772 406
büS Extension Cable 10 m	M12 plug to M12 socket, 10 m length	772 407
SIM Card	Actuator parameter storage card	291 773