The Burkert Type 6281 (221938) is a servo-assisted 2/2-way diaphragm valve, normally open (NO). Body and port: brass body, internal thread G1, orifice DN 20; sealing is made of NBR.
Circuit function and pressure range of version 221938
When de-energised, the flow path from port 1 (P) to port 2 (A) is open; energising the coil closes the valve. As a servo-assisted diaphragm valve, Type 6281 uses the medium pressure to switch. A minimum differential pressure of 0.2 bar is required, and according to the data sheet 0.5 bar to open the full cross-section; the pressure range of this version extends to 16 bar. The valve closes with damping and operates quietly. The Kv value for water is 8.5 m³/h. According to Burkert, this version opens in 120–1000 ms and closes in 150–3000 ms.
Actuator and connector of version 221938
The coil for 24 V AC 50 Hz (32 mm, encapsulated in epoxy resin) sits on the vibration-proof, centrally screwed coil system. The AC coil draws 24 VA at switch-on and 16 VA in holding mode; the rated power is 7 W. It is connected via plug contacts to DIN EN 175301-803 form A; with a cable plug, the valve achieves IP65. The cable plug Type 2518 is not included and available separately.
Technical data at a glance
Circuit function B, 2/2-way, normally open (NO) · Orifice DN 20 · Port connection internal thread G1 · Pressure range 0.2–16 bar · Kv value water 8.5 m³/h · Body brass · Seal NBR · Medium temperature -10 °C to +80 °C · Ambient temperature max. +55 °C · Voltage 24 V AC 50 Hz ±10 % · Rated power 7 W · Plug form A · IP65 with cable plug · Duty cycle 100 % · Installation length 80 mm · Weight 0.995 kg
Media and installation
According to the data sheet, it switches media that do not attack the body and seal materials. It can be installed in any position, preferably with the actuator facing up. As a dealer listed by Burkert, we source the valve directly from the manufacturer.
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