Coming soon
The Manual
The Domestic Heating Diagnostic Manual
A comprehensive, colour, lay-flat technical guide to understanding, testing and diagnosing domestic heating-control systems.
Heating Decoded. Understand the system. Diagnose with confidence.
Practical electrical-controls education, guided diagnostics and reference tools for heating professionals.
One manual and two apps, all still in development. Nothing is on sale yet.
Coming soonThe Domestic Heating Diagnostic Manual
The Heating Decoded family
One book and two apps, built to work together
Each product shows its real status. Prices and store links will appear here once they’re confirmed.
Planned sections
- Fault AtlasGuided fault-finding pathways
- SystemsS-Plan, Y-Plan and S-Plan Plus
- ComponentsWhat each control does
- TestingStructured test explanations
- Quick referenceKey information at a glance
In development
The Diagnostic App
Heating Decoded
Learn how heating systems operate, follow structured fault-finding pathways and access electrical-control reference material.
Planned sections
- IdentifyWhich control is on the wall
- CatalogueSearchable parts information
- ControlSwapDocumented compatibility
- MerchantsLinks to relevant listings
- FavouritesProducts you've saved
In development
The Part Finder App
Heating Decoded Part Finder
Identify heating-control products, access relevant merchant listings and use ControlSwap to explore documented compatibility information.
How they fit together
Learn it, diagnose it, identify the part
- 1
Learn it in the manual
The full explanation, in a printed book that lies flat on the job and doesn’t need a signal.
- 2
Diagnose it with the app
Structured fault-finding pathways and quick reference on your phone, linked back to the manual.
- 3
Identify it with Part Finder
Work out exactly which control is fitted, check the documented information and find merchant listings.
What makes it different
It teaches understanding, not just where to find information
Wiring diagrams and fault codes are easy to find. Knowing why a system is behaving the way it is, and what to test next, is the hard part.
Heating Decoded works through a method rather than a list of answers:
- 01
Understand the sequence
How the system is meant to run, step by step, before anything is touched.
- 02
Interpret the wiring
What each terminal and conductor is doing in that sequence.
- 03
Know what to expect
What a healthy system should show at each point.
- 04
Test safely
Safe isolation first, then the right test with the right meter setting.
- 05
Read the result
What the reading tells you, and what it rules out.
- 06
Move on logically
The next check follows from the last one, not from guesswork.
Subjects covered
- S-Plan
- Y-Plan
- S-Plan Plus
- Safe isolation
- Electrical testing
- Wiring-centre logic
- Controls
- Smart thermostats
- OpenTherm
- Components
- Diagnostic methods
Who it's for
Made for competent people working in the trade
This isn’t a DIY heating-repair site. The content assumes you’re qualified and competent to do the work.
Gas and heating engineers
Domestic engineers diagnosing control faults on site.
Electricians
Electricians working on heating controls and wiring centres.
Supervisors and technical managers
People who back up engineers and check the work.
Housing and maintenance organisations
Housing associations and maintenance contractors.
Colleges and training centres
Apprenticeships, courses and assessment centres.
For organisations
For employers, housing providers and training centres
One consistent technical reference across a team, with support for learning and new starters.
Bulk manual purchasing
Planned for colleges, training centres and employers.
Organisational app access
Licensing for teams is planned alongside individual subscriptions.
Never used to monitor people
Any future insight would be anonymous and aggregated. It will never rank, track or monitor individual engineers.
Knowledge creates confidence.
Understanding creates competence.
Competence creates safer systems.
Hear first when they're ready
Register your interest in the manual or either app, or ask us about bulk orders and organisational access.