The ST9400C in a 7-day Electronic Programmer which provides accurate time control for central heating systems with separate programmes for heating & hot water. ST9400C is suitable for replacing a wide range of programmers on the market & is a direct replacement for Honeywell ST6400 Programmers without the need for re-wiring. ST9400 programmers can be combined with other Honeywell Controls such as Room Thermostats Cylinder Thermostats Wiring Centres & Zone or Diverting Valves to form a fully automatic central heating control system.