Boiler Pressure Keeps Dropping? We'll Hunt Down the Hidden Leak in Kenilworth

Why Pressure Loss Becomes a Habit

A one-off pressure drop is usually obvious — a bleeding operation, a repaired joint, a drained radiator. When the gauge keeps sinking, something is actively wrong, and the most frequent repeat offenders are:

• A small persistent leak — weeps at radiator valve tails, compression joints and radiator pinholes are easy to miss because they evaporate or soak away. On sealed systems they are the commonest cause of recurring loss.
• A leaking pressure relief valve — designed to open at a set maximum pressure, it can be weakened by repeated discharges and then weep constantly through the discharge pipe outside. It looks like nothing happening, but the system quietly empties.
• A failed expansion vessel — without its air cushion, pressure spikes when the system heats, the relief valve discharges, and the system cools down below its starting pressure. The pattern repeats every heating cycle.
• A passing filling loop — a loop that is not fully closed, or has a faulty non-return valve, can pass water continuously.
• Leaks inside the boiler — internal seals, the pump seal or the automatic air vent can weep inside the casing, where the water drains away unseen.
• Micro-leaks in buried or underfloor pipework — invisible, often only detected by isolating sections and monitoring.

The Cost of Ignoring It

Beyond the nuisance, chronic pressure loss damages the system quietly. Every top-up introduces fresh water rich in oxygen and minerals, which speeds corrosion and builds sludge in radiators, valves and the pump. The boiler itself suffers too: running repeatedly at or below its minimum pressure stresses the pump and heat exchanger, and a boiler that keeps locking out is being switched hard on and off. Fixing the underlying cause is nearly always cheaper than the eventual repair bill for a system that has been run low for a year.

How We Trace the Loss

We take a history first: how often the gauge drops, whether it falls faster when the heating runs, whether the discharge pipe outside has ever dripped, and whether any radiator or joint shows staining. Then we work through the system — checking every accessible joint and valve, the filling loop, the expansion vessel's charge, and the relief valve's behaviour when the system heats. If nothing external explains it, we isolate sections of pipework and monitor pressure across each to focus the search, which is how hidden underfloor and buried leaks get pinned down. We keep to the water side throughout; we do not open the boiler casing or work on gas components.

The Repairs We Can Do

Most recurring pressure loss is fixable on the spot once found. We replace weeping radiator valves and failing joints, repair or replace corroded radiator sections, recharge or replace expansion vessels, replace worn pressure relief valves on accessible system pipework, and repressurise the system to the boiler maker's specified cold fill. Where the leak is inside the boiler casing — internal seals, pump seal or air vent — some of those water-side parts are within our scope and some involve gas-side components that are not; we will always tell you plainly which is which, and recommend a trusted Gas Safe registered engineer we work closely with for anything we cannot lawfully do.

Aftercare So It Stays Fixed

Once the system holds pressure, we will check inhibitor levels and recommend topping up if the water has been refreshed repeatedly, since fresh water feeds corrosion. We will show you the correct cold pressure reading and suggest a monthly glance at the gauge so any new loss is caught early. If the system water is heavily sludged from months of top-ups, we can quote a power flush separately.

How to Book the Trace

Tell us your boiler's make and model, how often you are topping up, and whether anything outside — such as the relief discharge pipe — has ever dripped. Same-day attendance may be available but is never guaranteed. You pay a booking fee when booking, labour is charged hourly at a rate that depends on how soon you need us, and the full repair cost is quoted and approved before we start. Parts are quoted separately. We cover the West Midlands.