When to use a professional
Separate ordinary water-side maintenance from work on a gas appliance or its final connection.
Quick answer
Do not use “it only touches water” as the test. HSE distinguishes some wet work around an appliance from work on the appliance, its safety systems and its final connection; gas work belongs with a Gas Safe registered engineer competent for that work.
Scope: Keep gas work and specialist heating work with appropriately registered competent people; verify water-fitting rules and manufacturer compatibility.
Four options to compare
Best for: A clearly identified tap, trap, hose or valve away from gas-appliance internals.
Main trade-off: Water Regulations, isolation, compatibility and damage risk still apply.
Must check: Exact pipe/fitting system, potable-water status, isolation and supplier notification where relevant.
Best for: Understanding whether a radiator-side or water-side task is outside the gas appliance itself.
Main trade-off: The physical boundary can be unclear and disturbing appliance controls or casing can cross it.
Must check: Ask a competent Gas Safe engineer when the work interfaces with the appliance.
Best for: Any work on the gas appliance, combustion, flue, safety controls or gas connection.
Main trade-off: This is not a DIY product-selection route.
Must check: Use a Gas Safe registered engineer qualified for the appliance and work type.
Best for: A suspected gas leak, combustion problem or carbon-monoxide alarm.
Main trade-off: Shopping comparisons are irrelevant during an incident.
Must check: Follow emergency instructions, leave the risk area where advised and use the current official emergency route.
“Boiler cupboard” or “radiator job” is too broad. Identify the exact component and whether the task could affect the appliance, gas supply, combustion, flue or safety controls.
This guide helps decide who should do the work. It deliberately does not provide steps for opening, disconnecting or modifying gas equipment.
What this guide cannot check
Do not claim universal safety, guaranteed suitability, professional approval or permission to undertake protected work. Check current instructions, exact identifiers and local circumstances before acting.