What a boiler fault code usually means
Modern combi boilers display a fault code when something's wrong rather than just stopping — the exact meaning varies by manufacturer, but common causes behind a "no heat" code include low pressure, a faulty sensor, or an ignition fault. Note the code before calling a plumber; it speeds up diagnosis considerably.
Understanding the labour vs materials split
Materials — pipework, fittings, a new boiler or bathroom suite — are often a smaller share of a plumbing quote than labour, particularly for jobs involving lifting floors or chasing walls. If a quote looks unusually cheap, check whether it specifies the same brand/quality of fittings as a competing quote, not just a lower labour rate.
Background checks and identity verification
Before booking, it's worth checking a plumber's trading history and identity, not just their registration — a landline or verifiable business address and reviews referencing specific jobs are stronger signals than a mobile number and a van sign alone.
Outside taps and garden plumbing
An outside tap needs its own isolation valve and, in colder areas, either an internal shut-off you can drain down for winter or a proper anti-frost design — a poorly installed one is a common cause of a burst pipe in cold weather. This is separate from the electrical requirements for any pond or irrigation pump also being installed.
When plumbing work needs a Gas Safe engineer instead
Plumbers can install and repair most water systems, but any work on a gas appliance or gas pipework — a boiler, a gas fire, a gas hob — is illegal for anyone who isn't on the Gas Safe Register, by law. If a job involves both plumbing and a gas connection (moving a boiler, for example), check whether your plumber is also Gas Safe registered before booking.
Boiler pressure and heating faults
Most combi boilers run best between 1 and 1.5 bar of pressure — too low and the heating cuts out, too high and the pressure relief valve can discharge. A plumber checking a heating fault will usually look at pressure, check for trapped air in radiators (bleeding), and check the pump and diverter valve before assuming a full boiler fault.
Shared water supplies in flats and conversions
In a converted property, check whether your flat has its own independent stopcock and supply, or shares one with other flats via a communal system. A shared supply can mean a repair affects your neighbours too, and sometimes needs freeholder involvement before work starts.
Plumbing work and home insurance
Escape of water is one of the most common home insurance claims in the UK, and insurers sometimes ask whether recent plumbing work was carried out by a registered professional when assessing a claim. Keep receipts and any commissioning paperwork for significant work, not just for the boiler.