We have two books which will help you find the information you need when working at a customer’s house, full of hints and tips with 99% of faults which has come from manufactures and 45 years experience on the tools.

Don’t leave home without them!

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Allow 14 days from posting.

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Our very popular book is an excellent reference for you to use on central heating wiring.

Central Heating Wiring & Controls Book 3

The aim of this book is to make wiring easier and more rewarding. It has been designed to help you carry out installations and fault finding on control circuits by giving you all the information you need in a clear and logical manner. 

We have worked closely with the technical departments to take their existing wiring diagrams and schematics and turn them into full colour illustrations which are much easier to understand and use. 

The most common control circuits in use in the UK are the three port (Mid Position) and two and three port zone circuits. This book therefore contains a greater number of diagrams for those circuits. 

For many years electricians and heating engineers have commented that wiring heating controls is a difficult subject to learn, (this book is easy to follow).

They want to be able to wire and test these circuits with confidence but the existing diagrams are not always easy to follow.

This book is for all levels from basic to advanced easy to follow.

What’s inside:

Schematics 23

Fault finding 55

2 Zone S Plan 51

Wiring Centres 14

Frost Protection 54

SMART Controls 46

3 Zone S Plan Plus 25

Programmer wiring 35

Mid Position Y Plan 15

Testing components 57

Diagrams in full colour 22

Fault Finding flow charts 10

This book is wire bound in A5 size

£25.00 including P&P no VAT. 


Allow 14 days from posting.


Central Heating Fault Finding Book

Written by a breakdown engineer of 45 years. George Staszak is the man who started Mr Combi Training “Hands on” fault finding and Wiring course for over 20 years until retiring in September 2022.

If you are an engineer going to service or repair a boiler you take tools

spanners screwdrivers etc. do you take a manual? No, don’t expect one to be there, Problem.

Don’t waste time guessing or phone a friend, this book has 99% of every fault known. Use the flow charts

Don’t go to any boiler without this book, no manual no problem.

In our Central Heating Wiring & Controls book you’ll find a vast array of information and diagrams.

What’s included:

By Pass 42

Gas valve 31

Fan testing 66

Polarity test 16

PCB testing 36

Pump testing 38

Pumping over 41

Boilers in lofts 45

Short circuit test 14

Factory flow charts 8

16 Popular faults 28

Plate to plate faults 43

Sequence of wiring 24

Diverter valve faults 46

Sequence of operation 25

All about expansion vessels 72

Fault isolation (what blows fuses) 22

*Refunds will not be made because of errors or omissions, content is supplied by manufactures in good faith. Please email us of errors / omissions.

Central Heating Fault Finding Book

The book is available in A5 size.

£25.00 each including P&P no VAT


Allow 14 days from posting.

CO/CO2 Chart

The special plastic paper is no longer available, soon it will be laminated “Order Today”

The printout will have 4 lines: 02, CO, CO2, Ratio. The CO2 is important because it’s shows HOW good or bad the boiler is performing.

First read the M.I. to see what it should be. White good, Orange call the manufacture for guidance, RED shut down ID. Printed on Flexi-plastic with easy to follow instructions, show the customer how their boiler is performing.

This should be done EVERY year, it’s a requirement not just for the guarantee


Allow 14 days from posting.

£5.00 each including P&P (no VAT)