The time clock is located on the boiler to control the central heating normally on combination boilers. The time clock brings the boiler on at pre-set times throughout the day so heating isn’t on 24 hours a day it allows the user to set and maintain the temperature of the room. Most people set their boiler to come on in the morning just before they get up, they then set the timer to turn the boiler off just before they leave for work. This is then repeated for when they arrive back from work the boiler comes on again and goes off just before they go to bed. The time clock is also referred to as the programmer, timer, time switch or just the boiler clock. They come in mechanical and digital versions depending on the customer’s requirements and they are now available as an App on a smartphone such as Nest & Hive.