Boiler Leaking Water?: Here’s What to Do

When your boiler is leaking water, you need to take action quickly. Here’s what could be causing these leaks and how you might be able to fix them.

Will my boiler stop leaking if I turn it off?

Yes, a leaking boiler will eventually stop leaking once it is turned off. Keeping the boiler on means it will try to refill itself with any remaining water in the heating system, so turning it off will prevent this from happening.

How do I know if my boiler is leaking water?

One of the first signs that your boiler may be leaking water is that it cuts out due to low pressure. Even after you top it up, you may notice that the pressure is still low. 

Another way you will be able to tell is if there are any actual pools of water by the boiler, or visible signs of watermarks. You may be able to see water running down the exterior of the connecting pipes, and sometimes there may be damp, mould or staining near the boiler. Water leaks can even cause warped skirting boards. 

Common reasons why a boiler may be leaking

Below are some of the most common reasons why your boiler may be leaking:

High water pressure 

Too little or too much water pressure can cause problems. One of the reasons why your boiler may be leaking is due to the fact that your boiler pressure is too high. 

You will be able to tell if the pressure is too high by checking the gauge on the front. If this is the case, it is likely that your boiler is trying to release some of this pressure. 

The valve needle on the gauge should be between 1 and 1.5, which is in the green zone. If it is any higher than this, in the red zone, you may need to bleed your radiators to relieve some of the pressure. 

Corrosion in the system 

Corrosion can be a problem in older boiler units as it causes rust and other debris to build up within your pipework. 

This corrosion can break down the rubber seals on the joint of two connecting pipes, which is where water may leak through. However, if the corrosion is widespread, it can affect the boiler itself which is what causes the leaks. If this is the case, you may need to have your boiler replaced. 

Faulty heat exchanger 

The heat exchanger is the element that allows your boiler to heat cold water. Unfortunately, a leak can be a sign that the heat exchanger is faulty and starting to decay. 

This isn’t a problem that you will be able to see and visibly diagnose yourself, as it involves taking off the boiler cover and looking inside.

Pin hole or split on an internal boiler component

Sometimes your boiler may develop a pinhole in one of the parts. It is common in some of the older boiler models. This will cause a fine spray of water, which may only become noticeable when you see a small drip on the left or right hand side. 

In this case, you need to call a Heating Engineer to diagnose the problem. The risk is that the fine spray hits the printed circuit board inside your boiler and blows this element, which is an expensive part to replace. 

How to fix a boiler leak

As we’ve mentioned, the first thing you should check is the pressure gauge on your boiler. This can be an easy fix by simply bleeding your radiators. 

If the pressure isn’t the problem, you should check for any leaks by dabbing a cloth on any visible pipe fittings or joints. To check, dab the area dry and wait to see if any water reappears. If it does, you can try tightening the joint with just a quarter turn of a spanner. 

If this still fails and you cannot determine the issue yourself, you should call a qualified Gas Safe heating engineer. 

At Lacey Plumbing & Heating, our engineers can be out quickly to help diagnose what the problem is. Our engineers will give impartial advice on the best course of action, finding the quickest solution to fixing your boiler. 

How can I prevent my boiler from leaking?

The best way to prevent your boiler from leaking is by having it serviced annually. Thorough boiler inspections can help to ensure that your boiler will be working as it should be, while diagnostic checks establish if there are any minor problems with the boiler. 

We offer simple, cost effective annual boiler service plans that are available for all your heating and plumbing needs.