This unique A-Z guide to central heating wiring systems provides a comprehensive reference manual for hundreds of items of heating and control equipment, making it an indispensable handbook for electricians and installers across the country. The book provides comprehensive coverage of wiring and technical specifications, and now includes increased coverage of combination boilers, recently developed control features and SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) boilers ratings, where known. In addition to providing concise details of nearly 500 different boilers fuelled by electric, gas, oil and solid fuel, and over 400 programmers and time switches, this invaluable resource also features numerous easy-to-understand wiring diagrams with notes on all definitive systems. Brief component descriptions are provided, along with updated contact and website details for most major manufacturers. Ray Ward has spent over 20 years as a specialist in the field of wiring domestic central heating systems and the knowledge he has gained from hands-on experience and staff training is now brought together in this comprehensive handbook. It is an essential reference source for all electricians and heating engineers. It provides product information from over 40 manufacturers and is fully updated to include more information on new technologies, combination boilers and efficiency ratings.