This concise guide to parts, wiring systems and ancillary equipment is destined to become a standard piece of kit in electricians' and heating installers' vehicles throughout the country. Ray Ward provides comprehensive coverage of wiring, technical specifications, availability and part alternatives for programmers, motorised valves, thermostats, and boilers suitable for domestic use, including combination and condensing boilers. This book contains information on over 340 programmers from 35 manufacturers, over 40 cylinder and 70 room thermostats, and over 200 gas boilers from 40 manufacturers. There are also over 70 easy to understand full page wiring diagrams with notes on all definitive systems. A brief description of components is provided, as is a guide to programmer and time switch interchangeability. Ray Ward has spent 20 years as a specialist in the field of wiring domestic central heating systems. He has also been involved in training staff, where he discovered the need for this handbook.