Gas revision, without the fluff.
Practical, no-nonsense revision for the UK domestic gas ACS assessments — CCN1, CPA1, CKR1, HTR1 and CENWAT — written to current standards. Study support, not a substitute for hands-on training under a registered assessor.
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7 guides on core gas safety
The core ticket everything else is built on: legislation, tightness testing, ventilation, pipework, gas rates, flues and unsafe situations.
The Complete CCN1 Guide: Core Domestic Gas Safety
The complete CCN1 core gas safety guide: gas legislation (GSIUR), tightness testing, ventilation, pipework, gas rates, unsafe situations and flue checks.
Tightness Testing & Purging for Domestic Gas
How to carry out a let-by and tightness test on a domestic gas installation: stabilisation, permitted pressure drop and purging — to current standards.
Gas Rates & Burner Pressure Explained
Calculating gas rate from the meter, checking working pressure and burner pressure, and what the readings tell you about a correctly set appliance.
Ventilation Requirements for Gas Appliances
Air for combustion and cooling: how ventilation free areas and room volumes are worked out for gas appliances, and when extra air vents are needed.
Pipe Sizing & Installation to BS 6891
Installing and sizing gas pipework to BS 6891: pressure drop, pipe routes, sleeving, protection and testing. The pipework essentials for CCN1.
Flues: Types, Inspection & Testing
Open-flued, room-sealed and fan-assisted flues explained, plus how flue inspection, flue flow and spillage testing are carried out.
Unsafe Situations & the GIUSP
Immediately Dangerous, At Risk and Not to Current Standards explained: classifying gas faults under the GIUSP, warning notices and turning off.
5 guides on combustion analysis
Using an electronic flue gas analyser to check combustion — the readings, the limits, and what to do when an appliance is out of tolerance.
The Complete CPA1 Guide: Combustion Performance Analysis
The complete CPA1 guide to combustion performance analysis: using a flue gas analyser, the CO/CO₂ ratio, interpreting results and acting on a fail.
Using a Flue Gas Analyser (FGA)
Step-by-step use of an electronic flue gas analyser (FGA): warm-up, zeroing, probe placement and taking a reliable combustion reading.
The CO/CO₂ Ratio Explained
What the CO/CO₂ ratio actually means, why it matters more than CO alone, the limits a domestic appliance should fall within, and how it's calculated.
Analyser Care & Calibration
Looking after a flue gas analyser: sensor life, water traps, filters and why calibration certificates matter for valid combustion results.
Handling a Failed Combustion Result
What to do when combustion readings are out of limits: likely causes, the checks to make, and the safe-to-use decision under current procedure.
5 guides on gas cookers
Installing, commissioning and servicing gas cookers: stability, flame supervision, ventilation by room volume and safe clearances.
The Complete CKR1 Guide: Domestic Gas Cookers
The complete CKR1 guide to domestic gas cookers: siting and stability, flame supervision, ventilation by room volume, clearances and commissioning.
Cooker Stability & Anti-Tip Devices
Why freestanding cookers need a stability bracket or chain, where the anti-tip device fits, and how it's checked at commissioning.
Flame Supervision Devices (FSD)
How a flame supervision device works on a cooker hob, grill and oven, what it protects against, and how to test it operates correctly.
Cooker Ventilation by Room Volume
How room volume decides whether a gas cooker needs purpose-provided ventilation or an openable window, with worked examples.
Clearances to Combustible Surfaces
Safe clearances above and beside a gas cooker, the rules for nearby combustible surfaces, and what manufacturers' instructions add.
5 guides on fires & space heaters
Gas fires and wall heaters to BS 5871: appliance types, flue flow and spillage testing, hearths, clearances, flueless safety and ventilation.
The Complete HTR1 Guide: Gas Fires & Space Heaters
The complete HTR1 guide to gas fires and space heaters: appliance types to BS 5871, flue flow and spillage testing, hearths, clearances and ventilation.
Flue Flow & Spillage Testing
How to carry out a flue flow test and a spillage test on an open-flued gas fire, why both matter, and what a failure tells you.
DFE & ILFE Fires Explained
Decorative fuel-effect and inset live-fuel-effect fires: the difference, their flue and ventilation needs, and the commissioning checks.
Flueless Heaters & ODS
Flueless space heaters and how the oxygen-depletion system (ODS/ASD) protects the room, plus the ventilation these appliances rely on.
Hearths, Clearances & Closure Plates
Hearth requirements, clearances to combustibles and the role of the closure plate when fitting a gas fire into a fireplace opening.
6 guides on boilers & water heaters
Central heating boilers and water heaters: boiler types, flueing, condensate, interlock and controls, Benchmark commissioning and combustion analysis.
The Complete CENWAT Guide: Boilers & Water Heaters
The complete CENWAT guide to central heating boilers and water heaters: boiler types, flueing, condensate, interlock and controls, and Benchmark commissioning.
Boiler Types Explained
Combi, system and regular boilers, condensing operation and room-sealed vs open-flued: how each works and how to tell them apart.
Condensate Handling
Why condensing boilers produce condensate, how to run and terminate the pipe correctly, and how to avoid freezing and blockages.
Boiler Interlock & Controls
What boiler interlock means, how room thermostats, programmers and TRVs work together, and why correct controls are part of commissioning.
Benchmark Commissioning
Commissioning a boiler to the manufacturer's instructions and the Benchmark scheme: the checks, the gas rate, and filling in the logbook.
Water Heaters Explained
Instantaneous, storage and multipoint water heaters: how each delivers hot water, their flueing and ventilation, and key safety checks.
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