The EPH Controls A27-HW is a 230V wired 2-zone time programmer providing independent ON/OFF scheduling for one heating zone and one hot water zone (or two heating zones) in domestic central heating systems. With three programming modes — 24-hour, 5/2-day, and 7-day — and up to 3 ON/OFF periods per day per zone, it delivers the flexible, reliable control expected on S-Plan and Y-Plan installations. A backlit LCD, copy function, holiday mode, and keypad lock make it equally installer-friendly and homeowner-friendly.
2 Zones
Heating + hot water
3 Modes
24h / 5-2 day / 7-day
3 per day
ON/OFF periods per zone
5 Years
Manufacturer warranty
Electrical Safety: This is a 230V mains-connected device. Installation must be carried out by a qualified electrician or competent heating engineer in compliance with Part P of the Building Regulations. Isolate all supplies before wiring. This product is not suitable for outdoor installation (IP20 rating — indoor use only).
System Compatibility: Designed for S-Plan (two separate motorised valve) and Y-Plan (mid-position valve) domestic central heating systems with 230V wiring centres. Compatible with most 230V room thermostats. Volt-free SPST contacts (2 channels) — verify compatibility with your wiring centre before installation.
Memory Backup: A 3-month battery backup retains all programmed settings if mains power is interrupted — so schedules, time, and date are preserved after power cuts without the need to reprogram. No need to re-enter settings after a power outage.
Three Programming Modes
Choose from 24-hour (same programme every day), 5/2-day (weekday and weekend programmes), or 7-day (individual programme for each day of the week). Each zone is programmed independently, with up to 3 ON/OFF time pairs per day — ideal for households with varying routines.
Backlit LCD & Simple Interface
The large backlit blue LCD displays time, date, zone status, and active programme clearly in all lighting conditions. Push-button controls and an intuitive menu structure mean programming is quick — even for homeowners unfamiliar with heating controls. The copy function duplicates a day's programme across multiple days with a single button press.
Holiday Mode & Overrides
Holiday mode suspends the normal schedule for a user-defined number of days, preventing unnecessary heating while the property is unoccupied. The +1 hour boost and advance function allow manual overrides so occupants can call for heat or hot water outside programmed times — useful for occasional late nights or early mornings.
Frost Protection & Keypad Lock
Built-in frost protection activates heating at 5°C to prevent pipe damage when the property is unoccupied in winter — even if the programmer is in holiday mode. The keypad lock prevents accidental or unauthorised changes to the programme, making it suitable for rental or managed properties.
Flexible Mounting Options
The A27-HW accepts both surface-mount (pattress) and recessed (back-box) installation via a simple 6-terminal wiring block. Its compact 140 × 99 × 35mm profile sits neatly alongside standard thermostats, and a conventional 1- or 2-gang back box is typically all that is needed for a direct replacement on most existing systems.
Volt-Free SPST Contacts
The volt-free SPST outputs (230V AC, 3(1)A per channel) drive motorised zone valves or wiring centre inputs directly. The 8VA power consumption keeps standby load negligible. Compatible with virtually all domestic 230V wiring centres and zone valve actuators from leading brands including Honeywell, Drayton, and Danfoss.
| Specification |
Value |
| Model |
A27-HW (2-Zone Programmer) |
| Power Supply |
200–240V AC, 50/60Hz, 8VA |
| Switch Rating |
230V AC, 3(1)A per channel |
| Contact Type |
Volt-free SPST — 2 channels |
| Number of Zones |
2 (heating + hot water, or 2 × heating) |
| Operating Modes |
24h, 5/2-day, 7-day |
| Programme Periods |
Up to 3 ON/OFF periods per day per zone |
| Override Functions |
+1HR Boost, Advance, Holiday mode |
| Frost Protection |
5°C built-in |
| Display |
Backlit LCD with blue LED |
| Memory Backup |
3 months (battery) |
| Ambient Temperature |
0°C to 45°C |
| IP Rating |
IP20 (indoor only) |
| Wiring Terminals |
6-terminal block |
| Width |
140 mm |
| Height |
99 mm |
| Depth |
35 mm |
| Weight |
220 g (approx.) |
| Warranty |
5 years (manufacturer) |
Is the A27-HW suitable for an S-Plan or Y-Plan system?
Yes. The A27-HW is fully compatible with both S-Plan (two motorised zone valves, one per circuit) and Y-Plan (single mid-position valve) wiring configurations. Connect Zone 1 output to the heating valve/circuit and Zone 2 to the hot water valve/cylinder thermostat circuit. Refer to the installation manual for the appropriate wiring diagram for your system type.
Can I use the A27-HW as a direct like-for-like replacement?
In most cases yes. The A27-HW uses a standard 6-terminal wiring block and fits a standard 1-gang or 2-gang back box. It is designed as a direct retrofit for older mechanical or digital programmers. Check the existing wiring against the A27-HW terminal map — common configurations such as Honeywell ST699 and Drayton LP722 replace directly.
What happens to the programme if there is a power cut?
The A27-HW includes a 3-month battery backup that retains the time, date, and all programmed schedules during a mains power interruption. When power returns, the programmer resumes from the correct time and date with no reprogramming required — an important advantage over basic programmers that revert to factory defaults after an outage.
How does the 5/2-day mode work?
In 5/2-day mode, you set one programme for weekdays (Monday–Friday) and a separate programme for weekends (Saturday–Sunday). This is ideal for households where occupancy and routine differ between the working week and weekends — for example, later wake-up times or extended heating periods at the weekend — without needing to programme all seven days individually.
Does the A27-HW comply with Part L (energy efficiency requirements)?
The A27-HW provides independent time control of heating and hot water, which is a requirement of Part L of the Building Regulations for most domestic heating systems. When used alongside a room thermostat, thermostatic radiator valves (TRVs), and a cylinder thermostat (where applicable), the system will typically meet Part L minimum control requirements. Always verify against the specific guidance document relevant to your installation type.
