Drayton 28mm Motorised 2 Port Zone Valve & Snap-On Actuator

Drayton 28mm Motorised 2 Port Zone Valve & Snap-On Actuator (6 Wire SPDT Switch) – MPN: 27205 is a robust motorised zone valve designed for controlling individual heating or hot water zones on sealed or open‑vented systems. It combines a 28mm compression brass valve body with a snap‑on 230V actuator, providing reliable on/off control with 100% tight shut‑off and simple industry‑standard wiring.

Key Features

• 2-port normally-closed zone valve – valve is normally closed and opens when powered, ideal for S‑Plan zoning of heating and hot water circuits.
• 28mm compression connections – larger bore for higher flow rates and reduced pressure drop on bigger primary circuits.
• Snap-on actuator – actuator clips on and off the valve body at the push of a side release button, allowing replacement without draining the system.
• 6-wire SPDT auxiliary switch – built-in changeover end switch (SPDT) with 6-core cable for flexible interlocking of boilers, pumps and other controls.
• Spring-return mechanism – power‑to‑open with spring return to closed when power is removed, providing fail‑safe shut‑off.
• 100% tight shut-off – designed for positive closure to prevent unwanted circulation and overshoot.
• Manual lever and position indicator – lever for manual opening during filling or override, plus visual indication of valve position.
• Replaceable actuator and motor – both motor and complete actuator can be replaced, extending system life and reducing downtime.

Technical Highlights

• Brand / Range: Drayton – Motorised Valves.
• Model / Part: ZA6/779-2 28mm 2-port zone valve with actuator (Part No. 27205).
• Valve type: 2-port, normally closed zone valve.
• Connections: 28mm compression (copper tube).
• Body material: brass forging.
• Motor voltage: 230V AC, ≈5W synchronous motor.
• Operation: energise to open, spring return to close.
• Max static pressure: 8.6 bar.
• Max differential pressure: approx. 0.5–0.7 bar (28mm zone valve).
• Flow characteristic (Kv): approx. 6.7–7.0 for 28mm valve (high flow for larger systems).
• Water temperature range: 2°C to 93°C.
• Max ambient temperature: 52°C.
• Cable: approx. 1m, 6-core (5 cores + earth) for SPDT end switch and motor.
• Switch rating: 24–230V AC, 3(1)A resistive.
• Approximate dimensions: height ~117mm, width ~124mm, depth ~70mm; valve body length ~105mm.
• Standards / certifications: conforms to EN 60730‑1 and related control standards.

Typical Applications

• Two‑port S‑Plan systems controlling separate central heating and hot water zones using 28mm primary pipework.
• Zoned heating systems in larger domestic properties or small commercial installations where high flow rates are required.
• Replacement for existing 28mm Drayton or similar 2‑port valves using industry‑standard wiring centres and control schemes.

Installation Notes

• Install the brass valve body in the correct flow direction (typically in through Port A, out through Port B) and ensure pipe ends are clean and deburred before tightening compression joints.
• Fit the actuator after pressure testing where possible; the snap‑on design allows actuator replacement without draining the system, but always isolate mains power first.
• Wire using the standard 6‑wire SPDT zone valve diagram in the wiring centre, ensuring correct connections to thermostats, programmer and boiler.
• Mount the valve where it is accessible for future servicing and where the position indicator and manual lever can be easily viewed and operated.