East Anglian Leak Detection
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Heating and boiler pressure

Central heating leak tracing once the boiler has been ruled out

Your boiler has been checked and passed, but the gauge keeps dropping. That usually means a central heating leak in a hidden pipe. Our engineer Charlie works from the surface to find it and confirm it.

Price agreed before you book

Traced under floors and in walls

Repairs guaranteed for 3 months

Call 07700 102 008 Get a quote

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Lines open 8am to 8pm, every day.

A sealed heating system sends the same water round and round, so the boiler gauge should barely move from week to week. Topping up every few days means water is getting out. Once the boiler is ruled out, the likely cause is a pipe under a floor, in a wall or behind units.

Heating leaks rarely make a puddle, so the gauge may be your only clue. No find, no fee on home water leaks does not cover central heating. Instead you get a price before booking, based on a half or full day's tracing, and an early find does not reduce it.

A pressure test gauge connected by a hose to a radiator valve to check a central heating system A thermal imaging camera showing the warm line of a heating pipe inside a living room wall beside a radiator

Where heating water escapes, and how we narrow it down

A central heating leak can sit anywhere the pipes run. Under the boards of an older house, it is most often a joint. Many homes built from the 1970s onwards have pipes in a concrete floor, where a pinhole can weep for months. Others hide in boxing, behind kitchen units or at a radiator valve that only drips when hot.

There is no single answer to how to find a central heating leak, because the floor decides the method. In concrete, warm water spreads through the screed, the thermal camera usually picks it up and tracer gas pins the point. Under timber boards, water drips into the space below, so the camera shows less and testing each pipe run on a gauge does more.

Signs the heating is losing water

Boiler losing pressure, no visible leak

The gauge drops and nothing looks wet. Water from a buried pipe can soak into concrete or dry off under boards before it reaches the surface.

Topping up more often than before

Once a month became once a week, then every few days. Leaks tend to grow, and the gap between refills hints at how much is escaping.

A warm patch on a hard floor

Tiles or laminate that feel warmer than the rest of the room, often between two radiators, can mean hot water spreading from a pipe beneath.

Damp beside a radiator pipe

A dark mark on a skirting, plaster bubbling low on a wall or a damp carpet edge near a radiator can mean a weeping joint or valve.

Who usually calls us about heating leaks

Owners told it is a system leak

The boiler passed its checks, yet the pressure still falls. A system leak means the loss is in the pipes or radiators, not the boiler, and finding which pipe is our job.

Newer homes with pipes in concrete

Many houses have heating pipes buried in screed, the smooth concrete layer under tiles or carpet. A leak there stays hidden, so thermal imaging is usually how we find it.

Landlords with a tenant topping up

A tenant keeps topping up and you cannot be there. Tell us at booking who will open the door, as we may ask you to pay before the visit is confirmed.

From your first call to a marked leak

1

Tell us the top-up story

Say how often the boiler needs refilling and from what reading, what the ground floor is made of, and whether sealer has gone in. Those answers shape the visit and the price.

2

Split the system and watch the gauge

We use the water meter to rule out the pipes feeding your hot taps, then close valves to split the heating into sections. Whichever section keeps losing pressure is the one we trace.

3

Heat, trace and double-check

With the heating on, the thermal camera follows the pipes and picks out spreading warmth. Tracer gas or pressure testing has to back it up before Charlie marks and photographs the spot.

Three tests behind most heating finds

Thermal imaging

Hot pipes show through tiles, carpet and laminate as warm lines, and a leak spreads warmth sideways from them. The heating has to have been running first.

Pressure testing

We close off part of the circuit and fit a gauge. If the reading holds, that part is sound; if it falls, we look there next.

Tracer gas

Used for a leak in concrete, or one too small for the camera. A hydrogen and nitrogen mix escapes at the hole and is picked up at the surface.

Typical heating jobs around the region

Half a bar a day near Bury St Edmunds

The property

A 1970s detached house near Bury St Edmunds on a concrete ground floor. The downstairs radiator pipes run in the screed and rise through the floor beside each radiator.

The problem

The owner was topping up about half a bar a day, and the carpet edge under the study radiator felt damp. Tightening the radiator valves had made no difference.

How we found it

Moisture readings peaked around one radiator pipe. With that radiator's pipes closed off and tested on a gauge, the pressure fell, and the thermal camera showed heat spreading below the floor.

The outcome

The pipe had corroded where it left the concrete, just under the carpet. Only a hand-sized patch of screed came out to replace that short length, quoted separately.

Warm streak under the boards of a King's Lynn terrace

The property

A Victorian terrace in King's Lynn with floorboards over a shallow space downstairs. The radiator pipes run in that space, through the low brick walls that hold up the joists.

The problem

The gauge needed bringing back up twice a week, yet no radiator, valve or visible pipe was wet. A plumber had lifted boards by each radiator and found them dry.

How we found it

With the heating hot, the camera followed a warm streak across the back room boards to a wider warm patch. Testing that pipe run alone on a gauge confirmed the loss.

The outcome

Lifting the boards over the mark showed a split in the copper where it was squeezed through one of those walls. A new length went in there and then, quoted separately.

Leak sealer in the heating of a Stevenage house

The property

A post-war house in Stevenage with a solid ground floor and a mix of copper and plastic heating pipes, some in the floor and some boxed in.

The problem

After weeks of topping up, the owner had poured leak sealer into the system. The pressure held for a while, then started falling again, more slowly.

How we found it

The owner mentioned the sealer at booking, so their heating engineer flushed the system first. Pressure tests found the section, thermal imaging located the leak and tracer gas pinned it down.

The outcome

The leak sat under the utility room floor. Once it was marked, the owner had the repair priced separately and sent our report in with a trace and access claim.

Heating leaks and trace and access cover

Some home policies include trace and access. If yours does, ask the insurer before booking whether they need to approve the work. The written report gives the location, methods, readings and photographs, and reaches you once the bill is paid. Start any opening up at our mark. The insurer alone decides whether to pay.

Common questions

That is the usual point to call us. Their checks cover the boiler; ours cover the pipes beyond it. Tell us what they tested and found, and we can agree a price for tracing the leak through floors and walls.

Sometimes. Mention it on the phone, because sealer can block part of the hole. The leak then slows, or pauses while we test, and nothing shows up. A heating engineer may need to flush the system out before testing is worth doing.

Yes, or at least able to run. The thermal camera only shows a leak once the pipes are warm, so we run the heating during the visit. If low pressure has locked the boiler out, top it up to its usual reading first.

Only the patch over the marked spot, and only once you go ahead with the repair. Nothing is lifted while we search, because the tests work through tiles, boards and concrete. Readings at the surface give the mark; uncovering the pipe is what proves it, so the opening starts small.

It can. Pipes to your hot taps are usually fed from the mains, so a leak on one tends to show on the water meter rather than the boiler gauge. We read the meter with the hot supply open, then closed off, to tell the two apart.

A heating engineer, if it needs one. If radiators stay cold or the boiler shows a fault after refilling, the cause may be sludge, a blockage or the system’s design. Our 3 month repair guarantee covers the pipe and joints we fit, not the boiler or radiators.

Heating leaks in your county

We trace heating leaks in homes of every age, from terraces with wooden floors to new houses with pipes in screed. For central heating leak detection near you, choose your county below.

Leak detection in Cambridgeshire Leak detection in Essex Leak detection in Suffolk Leak detection in Norfolk Leak detection in Hertfordshire Leak detection in Bedfordshire Leak detection in Buckinghamshire Leak detection in Greater London

Other leaks we trace

Water leak detection Leaking water main Leaking underfloor heating Shower leak detection Underground water leak detection Gas pipe leak detection Thermal imaging leak detection Acoustic water leak detection Tracer gas leak detection Commercial leak detection Trace and access leak detection Leak detection for landlords Water leak repair

Useful guides

Boiler overflow pipe dripping outside: what it means Central heating leak sealer: what it can and cannot do Hot water leak or cold water leak: how to tell which pipe is leaking Microbore pipe leaks: finding a leak in thin heating pipes

Boiler checked and still losing pressure?

Call 07700 102 008 with your top-up pattern and floor type. Lines are open 8am to 8pm, every day, and visits are usually booked within 24 to 48 hours.

Call 07700 102 008 Get a quote
East Anglian Leak Detection