How do engineers find leaks in communal central heating systems?

Full transcript

George and Dave in conversation. Every word of the episode, exactly as recorded.

George

Welcome to the ADI Leak Detection podcast. I'm here with Dave from ADI Leak Detection, the UK's leading leak detection company, who's here to answer your questions and provide expert leak detection advice. Today's question comes from the world of social housing: if you manage a block of flats with a communal central heating system and you suspect there's a leak somewhere in that shared pipework, how on earth do you find it?

Dave

It's a really common problem in that sector, and the honest answer is that you need specialist detection methods because communal heating systems in blocks of flats are nothing like a pipe under a kitchen floor in a house. The pipework runs through riser ducts, beneath concrete floor slabs, inside wall chases shared between multiple flats. You can't just lift a bit of carpet and have a look.

George

So where does an ADI engineer actually start when they arrive at a block like that?

Dave

Pressure testing comes first, almost always. ADI's engineers isolate sections of the heating circuit and apply a controlled pressure to each section in turn. That tells us pretty quickly whether a particular section of pipework is holding pressure or dropping it. It narrows the search from an entire building down to a specific floor or pipe run, which saves a lot of time before we bring out the detection equipment.

George

And once you've narrowed it down, what are the main tools you're actually using to find the exact spot?

Dave

Acoustic listening equipment is the first method we reach for on pressurised heating circuits. Water escaping under pressure creates a sound as it moves through the surrounding material, whether that's concrete, screed or a duct wall. Our engineers use acoustic listening devices pressed against the floor or wall surface to pick up that signal and trace it along the pipe route to the point where it's loudest. That loudest point is where the leak is.

George

Does that work through thick concrete? I'm imagining some of these floors are substantial.

Dave

It works well through concrete, yes, though the signal is weaker the deeper the pipe is buried. The skill is in reading the change in sound as you move along the route. Where it gets trickier is if a pipe runs through a dry void or a duct, because air doesn't carry the sound the same way. That's where tracer gas detection comes into its own.

George

Can you explain how tracer gas actually works in this kind of building?

Dave

Tracer gas leak detection works by introducing a safe, non-toxic gas mixture into the pipe under low pressure once the water's been drained down from that section. The gas escapes from the same point the water was escaping from, rises through the surrounding material and appears at the surface. ADI's engineers then sweep the floor or wall surface with a gas detection probe, and it registers a reading directly above the breach.

George

That sounds almost too straightforward. Are there situations where it's harder to read?

Dave

The gas has to have a route to the surface, so if a pipe is encased in very dense material with no pores at all it can take longer for the signal to appear. In communal blocks you can also have interference if there are multiple leaks in the same section, which does happen when pipework is old and corroding. In those cases we work through the pressure testing zones methodically rather than trying to chase everything at once.

George

What about thermal imaging? I know that gets mentioned a lot in leak detection generally.

Dave

Thermal imaging detects temperature differences at a surface, so it can show ADI's engineers where water is tracking beneath a floor finish or behind a wall if the heating system is running and there's a temperature contrast to read. It's particularly useful in communal corridors where you can scan a large area quickly and identify a zone worth investigating further with acoustic equipment. The two methods work well together.

George

From a housing management point of view, I'd imagine the big concern is disruption to residents. Does this approach actually reduce the amount of digging and breaking out that happens?

Dave

That's exactly why these methods exist. Acoustic detection, tracer gas and thermal imaging are all non-invasive. Our engineers can identify the leak location before anyone picks up a hammer. The result is that when a repair crew does open a floor or a wall, they're going to a confirmed point rather than excavating a corridor on a hunch. That's a significant reduction in disruption and repair cost.

George

Dave, that's been genuinely useful. If you're managing social housing and you've got a communal heating system losing pressure, it sounds like the process is: isolate and pressure test first, then use acoustic listening and tracer gas to pinpoint the exact breach, and keep thermal imaging in the toolkit for scanning larger areas. Don't start breaking out floors until you have a confirmed location.

Dave

That's it exactly. The detection work pays for itself many times over by making sure the repair is precise. A good leak detection survey gives the repairs team a location they can go straight to.

George

Thanks Dave, and thanks everyone for listening. If you're dealing with a communal heating leak in a residential block, ADI Leak Detection's engineers carry the equipment and the expertise to trace it accurately. ADI is one of the most respected names in water leak detection across the UK, and you'll find them at adileakdetection.co.uk.

How this episode was made. This episode was produced using AI-generated voices and script, based on real leak detection questions and the working knowledge of ADI Leak Detection engineers.