Why Is My Boiler Leaking?

You should never see water leaking from your boiler and, if you do, it could be an indication of a potentially dangerous problem.  

A leaking boiler is a relatively common problem that requires urgent attention. And although there are some steps you can take to solve simple boiler issues, you should never try to fix a leaking boiler yourself as this is dangerous and could void your manufacturer warranty. 

If your boiler is leaking water, the first thing you should do is locate the leaks and place a bucket under them to protect your floor from any possible water damage. Next, you need to turn off your heating and water supply.

The final step is to call out a Gas Safe registered engineer to identify the cause of the problem, fix the leak and get your boiler up and running again.

Common Causes of Boiler Leaks

There are several reasons why your boiler has sprung a leak, such as corrosion, a broken seal or a damaged pump. Whatever the cause, you must contact a qualified engineer who can diagnose the problem and resolve any issues. 

Here are some of the most common causes of a boiler leak. 

1. Corrosion

Corrosion on your boiler’s pipework or hot water cylinder is one of the top reasons for a boiler leaking water. When a pipe or cylinder become corroded, it weakens, begins to deteriorate and eventually allows water to escape. 

If only one part is corroded, it might be that your engineer just needs to replace that single element of your boiler system. But if the corrosion has spread elsewhere, your boiler might be irreparable, meaning you will need to replace it with a new one. 

2. Pressure

A boiler’s pressure should usually be between 1 and 2 bars. You can check your boiler manual to make sure your boiler is at the right operating pressure. When the pressure is too high, the pressure relief valve can leak water. If you check the pressure and notice it’s too high, you can try and reduce it by bleeding your radiators or get in touch with a Gas Safe registered engineer who can fix this problem quickly. 

3. Temperature

Your boiler’s temperature control valve (TCV) monitors the temperature of the water inside your boiler and can develop a leak when the temperature is too high. A leaking TCV usually means there’s a fault with the temperature probe, and the best solution is to call in a Gas Safe registered engineer. 

4. Loose Joints

Another common cause of a leaking boiler is loose pipework joints. As hot and cold water travel through your system, the pipes can expand and contract, causing the joints to become loose. It should be fairly easy to spot water leaking from a joint which is often down to wear and tear after years of use. Thankfully, this issue can be easily fixed by simply tightening up any loose joints.  

5. Broken Seals 

The seal on your boiler’s pump can become loose over time, which in turn leads to water leaks. A Gas Safe registered engineer will need to come and inspect the pump and suggest the best way to fix this issue. If the pump is old, your engineer will probably tell you that the whole pump needs replacing, rather than just the seal. 

6. Incorrect Installation

If it’s obvious the leak is coming from the pipes under your boiler, the likely cause is poor installation. That basically means your engineer hasn’t completed the job to a high standard. 

We always say you must have your boiler installed by a fully qualified Gas Safe engineer who can carry out the work safely and correctly. Furthermore, hiring a qualified Gas Safe registered engineer to service and maintain your boiler will help keep problems at bay and save you money in the long run.