Leaking Pressure Relief Valve (PRV)?

A leaking PRV can lead to water damage, energy waste, and safety hazards.

Pressure Relief Valves (PRVs) are crucial components in maintaining the safety and efficiency of a central heating system. PRV’s are designed to release water and reduce pressure, thus preventing potential damage.

What does a Pressure Relief Valve Do?

A Pressure Relief Valve regulates pressure to prevent damage to pipes, the boiler, and the entire central heating system. The PRV is connected to a discharge pipe that directs the expelled water safely away. 

Corrosion, material degradation, or high pressure can lead to a malfunctioning PRV, often indicated by leaking water or a hiss sound.

Leaking PRV Valve

Identifying a Leak in Your PRV

Look for Visible Signs

Check around the PRV foLr any signs of water leakage, such as dampness, puddles, or a continuous drip or spray. Corrosion or rust near the valve area can also indicate a long term problem.

Listen for Sounds

A hissing or gurgling sound can often accompany a leak, especially when the system is under high pressure.

Check the Pressure Gauge

An unusually high or fluctuating reading on your system’s pressure gauge can suggest a malfunctioning PRV.

Causes of PRV Leaks


The PRV is designed to release water when pressure exceeds a safe threshold. The PRV will leak if there is continuous high pressure in the system.


Over time the PRV valve and its components can corrode or wear down, especially in systems with poor water quality or those that are aging. Corrosion can lead to a fault or create small gaps where water can escape.


Sediment, scaling, or debris in the system can obstruct the PRV, preventing it from closing fully and leading to leaks.


A faulty valve may not operate correctly, leading to continuous leaking. Damage to the valve, such as cracks or broken components, can also cause leaks.


If the PRV is not installed correctly, it may not seal properly or might be subjected to undue stress, leading to leaks.


External environmental factors such as temperature fluctuations or the age of the PRV can affect its integrity and lead to leaks.

I Have A Leaking PRV – What Next?

If you notice that the PRV leaks water, especially during water heating, it likely indicates that your expansion vessel is faulty or requires repressurization.

A properly functioning expansion vessel accommodates water influx as pressure rises and releases it as the temperature, and consequently the pressure, drops.

A qualified plumber can adjust the expansion vessel to the correct pressure.

My PRV isn’t leaking, What else could be?

You may have a central heating leak if your Pressure Relief Valve is not leaking. A slow leak in your heating system could be the cause of your boiler losing pressure. 

Our heating leak experts are able to detect leaks on central heating systems using non-destructive techniques including Thermal Imaging, Acoustic Listening Devices and Tracer Gases.

Call us now on 0800 731 3843 if you suspect you have a central heating leak

ADI Leak Detection Customer Service Office Team