BURKERT 48171 is a Type 0290 servo-assisted 2/2-way diaphragm solenoid valve configured with a brass body, G 1 internal thread connections, and an internal orifice of DN 25 (25 mm). The valve opens reliably without requiring an operating differential pressure, covering a pressure span from 0 to 16 bar. Opening movement is supported by the fix-coupling between the main diaphragm and the magnetic core, while an integrated soft-kick function ensures gentle opening cycles. The magnetic coil is moulded in epoxy resin with thermal insulation class H, operating on 24 V AC at 50 Hz. Media sealing is provided by NBR elastomers for both the seat and external boundary, supporting media temperatures between -10 °C and +80 °C.

Circuit Function

The valve operates according to Circuit Function A (CF A). It is a 2/2-way servo-assisted solenoid valve that remains closed in the de-energized, unpowered state. When electrical power is applied to the coil, the magnetic plunger lifts the pilot seal and mechanically pulls the fix-coupled diaphragm off the valve orifice, enabling media flow from inlet port 1 (P) to outlet port 2 (A).

Technical Specifications

Parameter	Specification
Type	0290
Article number	48171 (048171)
Circuit function	A (2/2-way, normally closed)
Nominal orifice (DN)	25 mm (1")
Pilot control orifice	2 mm
Port connection	G 1 internal thread
Operating pressure	0 to 16 bar
Kv value (water, P → A)	10.0 m³/h
QNn value (gas)	10,700 l/min
Rated voltage	24 V AC, 50 Hz
Voltage tolerance	±10%
Electrical power consumption	Inrush: 120 VA; Holding: 32 VA (16 W)
Thermal insulation class	Class H (epoxy coil)
Duty cycle	100% ED continuous operation
Switching times (opening / closing)	100 to 250 ms / 700 to 2000 ms (measured at +20 °C, 6 bar outlet)
Body material	Brass
Seal material	NBR
Medium compatibility	Neutral gases and liquids (compressed air, water, hydraulic oils, oils without additives)
Medium temperature range	-10 °C to +80 °C
Maximum ambient temperature	+55 °C
Degree of protection	IP65 (with cable plug attached)
Electrical connection	DIN EN 175301-803 Form A plug (cable plug enclosed)
Weight	1.8 kg

Material Specifications

Item	Component	Material in Article 48171 (Type 0290 Family)
1	Coil	Epoxy
2	Stopper	Stainless steel 1.4105, 1.4113 or 1.4523
3	Shading ring (AC only)	Copper (Brass variant) / Silver (Stainless steel variant)
4	Spring	Stainless steel 1.4310
5	Magnetic core (armature)	Stainless steel 1.4105 or 1.4113
6	Core guide tube	Stainless steel 1.4303
7, 8, 9	O-rings	NBR (NBR, FKM, EPDM across variants)
10	Diaphragm plate	CuZn37 (Brass variant) / 1.4401 (Stainless steel variant)
11	Diaphragm	NBR
12	Body	Brass (MS)
13	Pilot valve seat	Brass (MS)
14	Seat seal	NBR

Dimensions

Dimensions for threaded body variants of Type 0290 are stated in millimeters (mm). For G threads, columns D1 and F1 apply; for NPT threads, D2 and F2 apply.

DN	A	B	D1 (G)	F1	D2 (NPT)	F2	E	L	SW	J	H
12	80.0	94.0	G 1/2	14.0	NPT 1/2	13.7	40	74.5	27	81	40
20	106.0	122.0	G 3/4	16.0	NPT 3/4	14.0	60	100.0	32	93	49
25 (48171)	110.5	131.0	G 1	18.0	NPT 1	16.8	70	115.0	41	98	49
32	120.0	145.0	G 1 1/4	20.0	NPT 1 1/4	17.3	85	126.0	50	106	49
40	124.0	154.0	G 1 1/2	22.0	NPT 1 1/2	17.3	85	126.0	60	106	49
50	176.0	211.0	G 2	24.0	NPT 2	17.6	115	164.0	70	133	72
65	176.0	218.5	G 2 1/2	27.0	NPT 2 1/2	23.6	115	179.0	85	133	72

Installation and Operation Guidelines

Pressure and Electrical Safety

Before loosening process lines or removing the valve, depressurize the system and vent all fluid lines. Before touching electrical connections, disconnect electrical power and secure against unauthorized restart.

• Upstream Filtration: To maintain reliable switching and seating, install a dirt trap with a mesh size of ≤ 400 µm upstream of the valve inlet. Foreign matter must not reach the pilot channels or seat areas.
• Mounting Position: Mounting orientation is arbitrary, though installing the valve with the actuator upright is recommended.
• Flow Direction: Observe the arrow stamped on the valve body. Fluid flow must correspond strictly to the indicated direction; reverse flow renders the valve non-functional.
• Mechanical Handling: Do not use the solenoid coil as a lever arm during pipe threading or tightening. Prevent sealing tape or liquid sealant from entering the valve cavity.

Brief Pressure Transient

A sudden pressure surge when the valve is closed may cause a momentary brief opening. Install system surge protection when operating with critical or hazardous fluids.

Electrical Installation

Electrical connection is established through the supplied DIN EN 175301-803 Form A cable plug. Assembly requires attention to electrical safety guidelines:

1. Ensure the supply voltage matches the coil rating of 24 V 50 Hz with allowable tolerance within ±10%.
2. Position the flat sealing gasket between the coil terminal face and the cable plug housing.
3. Tighten the central fastening screw to a maximum tightening torque of 1 Nm to achieve IP65 protection.
4. Connect the protective ground conductor (PE) and verify electrical continuity between the coil and the valve body.

Alternating Current Armature Hazard

With alternating current (AC) coils, a mechanically seized or obstructed magnetic core prevents full magnetic pull-in. This causes coil current to remain at inrush levels, overheating the coil and leading to thermal failure. Ensure the medium is clean and the core area remains unobstructed.

Maintenance and Troubleshooting

Long Downtime Maintenance

When the valve remains energized or unactuated over prolonged system shutdowns, perform 1 to 2 switching cycles per day to maintain functional readiness.

Fault	Possible Cause	Corrective Action
Valve does not actuate	Short circuit or coil winding interrupted	Check coil resistance and supply voltage; replace coil if burnt
	Operating pressure out of permissible range	Verify operating pressure is within 0 to 16 bar
	Core or armature guide tube contaminated	Disassemble valve upper section and clean foreign matter
Valve does not close	Valve interior or seat soiled	Inspect main diaphragm, seat face, and pilot orifice; clean contamination

Spare Parts and Ordering Overview

Spare parts can be ordered using the article number 48171 from the nameplate. Bürkert offers SET 1 (coil set) and SET 3 (wearing part set including diaphragm, springs, and elastomer seals). Only genuine manufacturer replacement parts must be used.

Type 0290 valves can be operated in combination with Type 2518 cable plugs (available unwired, with LED, varistor, or rectifier modules) and Type 1087 analogue or digital timing modules mounted directly to the Form A interface.