What to do with a leaking boiler

It’s a moment we all dread: a leaking boiler. It’s quite a serious problem, and it means that one or more of the components inside (perhaps a seal or a value) are broken. Leaks can also cause corrosion and rust, as well as short-circuiting your system, which can be incredibly dangerous. In some cases, they can even lead to bigger issues around the house, like structural problems. With this in mind, you need to get a leaking boiler sorted as quickly as possible.

So, what should I do?

Don’t panic, because there are experts who can help you. Unless it’s your job, you should never attempt to repair it yourself. Working with gas can be extremely dangerous, and gas boiler repairs should always be carried out by trained and fully qualified engineers, contact a British Gas engineer for example.

As soon as you identify a leak from your boiler, shut off the gas and water supplies to your boiler immediately. Then make sure you call for a Gas Safe Registered engineer straight away. They’ll be able to assist you.

But why is my boiler leaking?

Finding out what’s causing a boiler leak isn’t always easy; often, the engineer will need to take apart the unit in order to see what’s wrong (that’s another reason why you should never do it yourself). Below you’ll find some of the most common reason for leaks, and bear in mind that sometimes taking care of your boiler can help to prevent leaks in future – regular servicing to keep it in good shape is always a good idea.

Remember that our guide below is for your information only. Like we said, as soon as you see a leak in your boiler, it’s time to get the experts in.


Corrosion is common

This is the main cause of boiler leaks. Corroded pipes allow water to escape, and this can result in reduced pressure and inefficient running. If the corrosion is just on one valve or pipe, then solving the problem will be as simple as replacing a single component. It’s not a difficult job for a trained engineer.

Sometimes, though, the corrosion can be more widespread. In situations like this, it can be cheaper and safer to get a brand-new boiler rather than patching up a bigger problem.

What does the pressure valve say?

If your leak is coming from the pressure value, it usually means that the boiler’s pressure is too high. The optimum safe pressure is around 1 bar (or 18-21 PSI), but when it goes above this, you’ll find that water leaks out from the pressure release valve in an attempt to let out the excess pressure and stop to whole boiler from bursting.

Limescale and other obstructions can lead to increased boiler pressure, and it must be removed before the valves can be resealed.

Look for the temperature valve

If there’s a leak coming from the temperature valve, the temperature of your boiler may be too high. This can be caused by temperature sensor faults, and if so, they’ll need to be replaced; otherwise, scalding hot water could come out of the pipes and cause serious injury.

Perhaps it’s the pipe fittings or pump seals

If water is coming out of your pipe fittings, this could mean that your boiler has been incorrectly fitted. When you call in a Gas Safe Registered engineer, they will do their best to solve the problem. But unfortunately, depending on how poor the installation is, this isn’t always possible. In the worst case scenario, you’ll need to replace the whole boiler, which is likely to be a costly exercise.

If it’s leaking from the seals of the boiler pump, then the pump will either need to be resealed or replaced.

When was your last service?

Regular servicing is a great way to ensure your boiler is running smoothly. Any potential issues will be identified before they cause you a problem, so you won’t have to worry about being stuck without heating or hot water unexpectedly.