Boiler Repair & Servicing

Boiler Pressure Problems

If your boiler pressure keeps dropping, creeping up, or won't hold steady, we'll find out why and put it right rather than just topping you up and hoping. R.K Plumbing & Heating are Gas Safe registered for domestic gas work, registration 568345, and we cover Brighton, Hove and the surrounding Sussex towns.

Call 01273 911551
Copper risers with a filling loop, pressure gauge and Vaillant wireless receiver in a stripped cupboard

What we check and fix

Boiler pressure trouble usually comes down to one of a handful of causes. Here's what our visits typically cover.

Low Pressure Diagnosis

Tracking down leaks, weeping joints or air introduced during radiator bleeding that are dragging your pressure down.

High Pressure & Overfilling

Checking the filling loop, expansion vessel and pressure relief valve when pressure keeps climbing too high.

Repressurising & Rebalancing

Restoring your system to the correct working pressure and making sure it holds steady afterwards.

Component Repair & Replacement

Fixing or replacing faulty expansion vessels, pressure relief valves or filling loops when repeated top-ups aren't the real answer.

Why your boiler pressure won't sit still

A boiler that keeps losing pressure, or one that reads too high and keeps shutting down, is telling you something. It's rarely just a case of pressing a button. Sealed central heating systems rely on stable pressure to circulate water properly and heat your home safely, so when the gauge won't settle it usually points to a leak, an air problem, or a faulty component somewhere in the system.

We start by checking the gauge and asking about recent history, whether you've bled radiators, whether the pressure loss is gradual or sudden, and whether it's happened before. From there we work through the likely causes: pipe joints, radiator valves, the filling loop, the expansion vessel and the pressure relief valve. If it's simply a case of topping up after bleeding radiators, that's a quick job. If it's a recurring leak or a failing component, we'll explain what we've found and what it'll take to sort properly.

Topping up the pressure fixes the symptom for a day. Finding the cause fixes it for good.

We know it's unsettling when your heating keeps cutting out or the boiler starts flashing warning lights, especially in the colder months. Our job is to take the guesswork out of it, work tidily in your home, and leave you with a system that holds its pressure and a clear explanation of what we did.

More information

Common causes we come across

  • Slow leaks in pipework, radiator valves or joints that gradually drop the pressure over days or weeks
  • Air after bleeding radiators, which lowers pressure and needs a straightforward top-up
  • Filling loop issues, where a loop left slightly open or passing water lets pressure creep back up
  • Expansion vessel or pressure relief valve faults, which are common causes of high pressure and safety shutdowns

We are based in Woodingdean and cover Brighton, Hove, Worthing, Lewes, Shoreham-by-Sea, Haywards Heath, Seaford, Burgess Hill and surrounding Sussex towns. Boiler pressure is one of the most common heating callouts we do, alongside general boiler and heating repairs, and it's usually something we can diagnose and resolve in a single visit. As an accredited Vaillant installer, and Gas Safe registered for domestic gas work under registration 568345, we'll always tell you honestly whether a repair or a component replacement is the right call, and we won't recommend more than the system actually needs.

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Before you book

Answers to what people usually ask us before booking a boiler pressure call-out.

Why does my boiler pressure keep dropping?
The most common cause is a small leak somewhere in the system, though it can also happen after bleeding radiators, which releases air and lowers pressure slightly. If it's dropping repeatedly rather than as a one-off, it's worth getting it checked rather than just topping it up each time.
Is it safe to top up the pressure myself?
For a minor, one-off drop after bleeding a radiator, a careful top-up using the filling loop is usually fine. If pressure keeps falling or rising again soon after, that points to an underlying fault that a top-up won't solve.
What does high boiler pressure usually mean?
It's often down to overfilling, a filling loop that isn't shutting off properly, or a fault with the expansion vessel or pressure relief valve. High pressure can trigger your boiler to shut down as a safety measure, so it's worth getting checked rather than ignored.
How quickly can you come out?
We aim to get to boiler pressure issues promptly, especially if you've lost heating, since it's one of the more common calls we get. Give us a call on 01273 911551 and we'll talk through timing based on what you're experiencing.
Will you need to come back more than once?
Often it's a single visit to diagnose and fix, but if the cause is a hidden leak or a component that needs ordering in, we'll explain that clearly and arrange a follow-up rather than guessing.
Are you qualified to work on my boiler?
Yes. We are Gas Safe registered for domestic gas work, registration 568345, and an accredited Vaillant installer, and we work on boilers and heating systems across makes as part of our general domestic plumbing and heating service.
Do you cover my area?
We are based in Woodingdean and cover Brighton, Hove, Worthing, Lewes, Shoreham-by-Sea, Haywards Heath, Seaford, Burgess Hill and surrounding Sussex towns.
What if the pressure problem turns out to be part of a bigger heating issue?
We'll always tell you honestly if what looks like a pressure fault points to something larger, such as an ageing boiler or a wider heating system issue, and talk through your options before doing any further work.

Let's sort your boiler pressure

Call 01273 911551 or get in touch online and we'll talk through what's happening before arranging a visit.

Call 01273 911551