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.
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.
Plumbing emergencies — what to do first
For a burst pipe or major leak, turn off the water at the stopcock (usually under the kitchen sink or where the supply enters the property) before calling anyone — this limits water damage while you wait. For no hot water or heating, check the boiler pressure gauge first; a common cause is low pressure, which some homeowners can safely top up themselves via the filling loop.
Hard water and your plumbing
In hard water areas, limescale builds up inside pipes, taps, showerheads and boiler heat exchangers over time, gradually reducing efficiency and flow. A plumber working in a hard water area may recommend a water softener or scale inhibitor as part of a boiler installation, particularly for a system that's expected to last 10+ years.
Do you know where your stopcock is?
Every property has a main stopcock (usually under the kitchen sink, though sometimes in a different location in older or converted properties) that shuts off the water supply. Knowing where it is and checking it turns freely, before you need it in an emergency, is one of the simplest things a homeowner can do.
Plumbing regulations, FAQ
Do I need a certificate for a new bathroom? There's no single certificate like Part P for electrics, but any work must comply with Water Fittings Regulations, and gas-connected work needs a Gas Safe engineer. Can I do my own plumbing? Straightforward repairs, yes; anything affecting the public water supply (like a new connection) should go through a WaterSafe-approved plumber.
Connecting new kitchen appliances
A new dishwasher or washing machine needs its own isolation valve and a suitable waste connection — if you're changing from an old appliance in a different position, this sometimes means new pipework rather than just reconnecting to the old point.
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.