Horstmann (Secure) Diadem Programmer
This twin circuit hot water and central heating programmer with indicator lights has 16 programmes available for fully pumped systems including independent programming of heating and hot water and 10 programmes for gravity HW/pumped CH systems.
Programmes allow permanently ON or OFF On all day or ON/OFF twice a day. An advance switch gives temporary override without altering settings. The Diadem is ideal for gravity systems and fully pumped systems with spring return zone valves. A new backplate is included with the 425 Diadem.
Compatible alternatives with same backplate & wiring:
Horstmann H21XL - 24 Hour digital programmer with boost holiday & 5 year warranty
Horstmann H27XL - 7 day digital programmer with boost holiday & 5 year warranty