The Drayton 22mm Motorised 2 Port Zone Valve & Snap-On Actuator (MPN: 27100), also known by its full model reference ZA5/679-2, is the industry-standard zone valve for controlling individual heating or hot water circuits in domestic wet central heating systems. It pairs a 22mm compression brass valve body with a low-energy 230V snap-on actuator, giving installers a fast-fitting, easily serviced valve with 100% tight shut-off and the familiar 5-wire SPST end-switch wiring used across S-Plan heating and hot water zoning.
22mm
Compression Connections
2-Port
Normally-Closed Valve
230V
Snap-On Actuator
8.6 bar
Max Static Pressure
14 sec
Motor Opening Time
EN 60730-1
Control Standard
2-Port Normally-Closed Valve
The valve body is closed when de-energised and opens on demand, making it ideal for S-Plan zoning of central heating and hot water circuits.
22mm Compression Connections
Fittings suit standard 22mm copper pipework found in most domestic primary systems, giving good flow with low hydraulic resistance.
Snap-On Actuator
The actuator clips on and off using a side release button, so the actuator or motor can be replaced without draining down the system.
5-Wire SPST End Switch
A built-in single-pole, single-throw auxiliary switch provides boiler and pump interlock via the industry-standard 5-core cable, wired the same way as most other UK 2-port zone valves.
Spring-Return Fail-Safe
Energise-to-open operation with a spring return to closed when power is removed, so the valve fails safe in the closed position.
Manual Lever & Position Indicator
A manual lever allows filling and override, alongside a clear visual indicator of valve position for quick diagnostics.
Important Safety Information
This is a mains-voltage (230V) electrical device. All wiring and electrical connection work must be carried out by a competent person in accordance with BS 7671 (IET Wiring Regulations) and current Part P Building Regulations. Always isolate the electrical supply before removing or fitting the actuator.
Good to Know
The full model reference is ZA5/679-2 and the valve is built from separately orderable parts: the 679-2 valve body and the ZA5 actuator can each be replaced independently, so a failed motor doesn't mean replacing the whole valve.
Technical Specification
Identification
Manufacturer Part Number (MPN)
27100
Model Reference
ZA5/679-2
Brand
Drayton
Country of Origin
UK
Valve
Valve Type
2-Port, normally-closed zone valve
Number of Ports
2
Connections
22mm compression (copper pipe)
Valve Body Material
Brass forging
Kv Value
4.8
Maximum Differential Pressure
0.7 bar
Maximum Static Pressure
8.6 bar
Water Temperature Range
2°C to 93°C
Maximum Ambient Temperature
52°C
Actuator & Electrical
Actuator Type
Snap-on, 230V synchronous motor
Motor Supply
230V AC, 50Hz, 5W
Valve Operation
Energise to open; spring return to close
Motor Opening Time
Approx. 14 seconds
Spring Return Time
Approx. 6 seconds
End Switch Type
5-wire SPST auxiliary switch
Switch Rating
24V–230V AC, 3(1)A
Cable
1m, 5-core flex
Dimensions
Width
110mm
Height
120mm
Depth
70mm
Minimum Head Clearance
40mm
Minimum Side Clearance (from spindle centre)
60mm
Standards & Warranty
Compliance
EN 60730-1
Manufacturer Guarantee
1.5 years
Typical Applications
Two-port S-Plan systems providing independent control of central heating and stored hot water zones. Zoned heating systems in small to medium homes using 22mm primary pipework. Replacement valve for existing 22mm Drayton or compatible 2-port valves wired with the standard 5-wire zone-valve scheme.
Installation Notes
Install the brass valve body observing the correct flow direction arrow, using clean, deburred pipework and suitable jointing on the 22mm compression fittings. Fit or replace the snap-on actuator after pressure testing where possible, and always isolate the mains electrical supply before any electrical work. Wire the valve using the standard 5-wire SPST zone valve diagram via an appropriate wiring centre, interlocked with room and cylinder thermostats and boiler controls. Position the valve so the actuator, manual lever and position indicator remain accessible for future servicing and diagnostics.
Frequently Asked Questions
What is the difference between MPN 27100 and the model reference ZA5/679-2?
They refer to the same product. 27100 is Drayton's ordering part number for the complete valve and actuator assembly, while ZA5/679-2 is the underlying model reference combining the ZA5 actuator with the 679-2 valve body.
Can the actuator be replaced without draining the heating system?
Yes. The snap-on actuator clips off the valve body at the push of a release button, so the actuator or motor can be swapped without needing to drain down the system.
Is this valve suitable for hot water zoning as well as heating?
Yes. As a 2-port normally-closed valve, it is commonly used to independently control either the heating circuit or the hot water cylinder circuit in an S-Plan system.
What wiring standard does this valve use?
It uses the industry-standard 5-wire SPST wiring scheme common to most UK 2-port zone valves, allowing it to be wired through a standard heating wiring centre and to replace most other makes using the same scheme.
What happens to the valve if there is a power cut?
The valve is spring-return and fails safe: if power is lost, the spring drives the valve fully closed within approximately 6 seconds.
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
Documentation
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