Immersion heaters and hot water cylinders
An immersion heater is an electric backup for heating water in a cylinder, useful if the boiler fails or as the main hot water source in an all-electric property. If yours is tripping the electrics or not heating water, it's sometimes the heating element itself rather than the boiler or cylinder at fault.
Three steps to hiring the right plumber
First, check they're registered with a WaterSafe scheme (or Gas Safe too, if the job needs it) and ask for the registration number. Second, get a written quote that separates labour from parts. Third, ask what happens if the job uncovers a bigger problem — a good plumber will tell you before continuing, not after.
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.
Protecting pipes in cold weather
Pipes in unheated spaces — lofts, garages, outbuildings — are the most common source of a winter burst pipe once temperatures drop below freezing for a sustained period. Lagging exposed pipework and keeping heating on a low constant setting during a cold snap, rather than off, are the two most effective preventive steps.
What WaterSafe registration means
WaterSafe is the umbrella body for the UK's Approved Contractor Person schemes (including APHC, CIPHE, WIAPS and SNIPEF). A WaterSafe-approved plumber has been assessed on their knowledge of the Water Fittings Regulations, which exist to stop poor installation work or substandard products contaminating the drinking water supply — not just general plumbing competence.
Finding a hidden leak
A leak inside a wall or under a floor isn't always obvious until it shows as a damp patch or a high water bill. Plumbers use damp meters, thermal imaging or (for harder cases) tracer gas to locate a hidden leak without having to open up an entire wall speculatively — worth asking about before agreeing to exploratory work.
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.
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.