Boiler Advice
Boiler and Heating Guides
Browse boiler and heating guides for London homeowners, covering domestic gas boilers and central heating, from pressure and fault codes to radiators and servicing. Choose your situation and follow your appliance instructions. Never open the boiler casing or work on gas. If you smell gas, leave and call the National Gas Emergency Service on 0800 111 999 from a safe place.
Call with your postcode, the boiler make and any fault code showing.
- Gas Safe registered: 648977
- Phone line open 24/7
- Same-day appointments available
Safety: gas smells, carbon monoxide and checking an engineer
If you smell gas, leave the property and call 0800 111 999 from a safe place. Avoid flames and electrical switches. Only ventilate or turn off gas at the meter if safe, without delaying your exit.
For suspected carbon monoxide exposure, get outside into fresh air and seek medical help through NHS 111, or 999 for serious symptoms. Then call 0800 111 999; this must not delay medical help. Carbon monoxide has no smell. Treat a sounding alarm as real and do not re-enter until advised it is safe.
- Smell gas? What to do right now: immediate gas-escape action.
- Carbon monoxide: symptoms, alarms and what to do: recognise warnings and respond.
- How to check a Gas Safe engineer: check identity and work categories.
Boiler pressure
Choose the pressure guide for a gauge reading, recurring loss or component explanation. Repeated topping up is not a fix for an unresolved fault.
- Boiler pressure and topping up: understand readings and manufacturer-permitted topping up.
- Why your boiler keeps losing pressure: understand recurring loss and assessment.
- Expansion vessels and pressure relief valves explained: learn what these components do.
Boiler fault codes and resets
Start with your boiler’s manufacturer, model and full displayed code. Do not keep resetting a boiler that returns to a fault.
Vaillant and Worcester Bosch fault-code guides
Choose your manufacturer, then check the relevant model.
- Vaillant boiler fault codes: find guidance for the relevant model.
- Worcester Bosch boiler fault codes: explore model-specific display guidance.
Ideal, Baxi and Glow-worm fault-code guides
Choose the guide matching the name on your boiler.
- Ideal boiler fault codes: explore Ideal display explanations.
- Baxi boiler fault codes: find guidance for your Baxi model.
- Glow-worm boiler fault codes: explore Glow-worm fault displays.
- Boiler fault codes explained: understand displays and their diagnostic limits.
- How to reset a boiler safely: check when instructions permit a reset and when to stop.
Boiler problems: choose what has happened
Choose the problem you can observe, even if you do not know its cause.
No heating, no hot water, a leak or a frozen pipe
Start with the guide matching what has happened at home.
- No heating or no hot water: find permitted user checks.
- Leaking boiler: what to do: understand risks and next steps.
- Frozen condensate pipe guidance: check the safety limits before considering action.
Boiler noises and diverter-valve explanations
Explore an unfamiliar sound or component without assuming a diagnosis.
- Boiler noises explained: explore sounds without assuming their cause.
- Boiler diverter valves explained: understand the component and why symptoms need assessment.
Radiators and heating controls
Choose a guide for the radiator or control problem you have, or the change you are planning.
Cold radiators, bleeding and balancing
Start with the cold-radiator guide if you are unsure.
- Radiator cold or not heating up: explore cold patterns and possible causes.
- How to bleed a radiator: learn when bleeding helps and when it will not.
- How to balance radiators: understand uneven room heating.
Radiator leaks, valves and turning a radiator off
Choose the leak, valve or shut-off task you need.
- Leaking radiator or radiator valve: understand what to do about water leaks.
- Thermostatic radiator valves explained: learn how TRVs work and why they stick.
- How to turn a radiator off: understand shut-off and isolation limits.
Thermostat problems, smart controls and radiator sizing
Choose troubleshooting for a fault or planning for a change.
- Thermostat not working: find user-level checks for control problems.
- Smart thermostats and heating controls explained: compare functions and compatibility considerations.
- Choosing radiator size and heat output: understand sizing factors.
Boiler and heating decisions
Use these guides to weigh up repair, replacement, servicing and heating-system maintenance.
Repair or replace, and choosing a boiler type
Consider repair first, then explore boiler types if needed.
- Repair or replace your boiler?: assess repair before considering replacement.
- Combi, system or regular boiler?: understand the different arrangements.
- Boiler repair costs in London: typical London ranges for diagnosis and repairs, and what moves a price.
- How much does a new boiler cost in London?: typical supplied-and-fitted ranges by boiler type.
Boiler servicing and manufacturer warranties
Choose maintenance guidance or information about manufacturer conditions.
- Boiler servicing: checks, timing and frequency: understand the maintenance visit.
- Boiler warranties and annual servicing: explore service records and manufacturer conditions.
Powerflushing, magnetic filters and inhibitor
Understand cleaning, filtration and inhibitor before considering work.
- Powerflush explained: understand system cleaning and suitability.
- Magnetic filters and inhibitor explained: distinguish filtration from corrosion protection.
Boiler repair, servicing and gas work
Need help with a boiler problem in London?
For help with a boiler problem in London, call All Service 4 U on 020 3740 6785 and ask about our Gas Safe registered engineers. Call us 24 hours a day, 7 days a week. Describe the symptom and, if safely available, share the make, model and full displayed code.
020 3740 6785
