Combi Boiler FAQs
Common questions about combi boilers — how they work, who they suit, and what to expect.
5 questions answered by our Gas Safe engineers
What is a combi boiler?
A combi (combination) boiler provides both central heating and instant hot water from a single unit, without needing a separate hot water cylinder or cold water tank.
Is a combi boiler right for my home?
Combi boilers are ideal for properties with 1–3 bedrooms and up to 2 bathrooms. Larger homes may benefit from a system boiler with a cylinder for better hot water flow rates.
Why is my combi boiler not producing hot water?
Common causes include low water pressure, a faulty diverter valve, a tripped thermostat, or a fault code on the display. Check the pressure gauge first — it should read 1–1.5 bar.
Can a combi boiler run a power shower?
Standard combi boilers cannot run a traditional power shower (which requires a pump and tank). However, you can use an electric shower or a mixer shower with a combi.
How long do combi boilers last?
A well-maintained combi boiler typically lasts 10–15 years. Annual servicing significantly extends the lifespan.
Still have a question?
Our Gas Safe engineers are happy to answer any boiler questions. Call or message us.
Contact Us