What Has Caused My Boiler Leak?

In the occasion of a boiler leak, contact a gas engineer immediately. Gas appliance repairs should only be implemented by a registered gas safe engineer.

Determining the cause of a boiler bleed.

Generally, a boiler leak is a result of a broken internal seal or valve. The consequences of this can be corrosion and rust throughout the whole system and your boiler can short circuit.  Repairs can often be the solution of the bleed, but sometimes a replacement is necessary.

Finding where the boiler leak is emerging from is very difficult, as identifying whether it’s seeping out of the bottom or something inside the boiler is a challenge, especially with the boiler casing.


Below is a list of components and how they can cause water to escape:

  • Corrosion – Corrosion is the most common cause of boiler leaks throughout the UK. Overtime, boiler elements like pipes become corroded. If it is only one component that has been affected, it can just be replaced.  However, when the corrosion is extensive, a boiler replacement will be more cost-effective than trying to repair all the parts damaged.


  • Temperature Valve – A flaw with the temperature probe can cause the temperature settings to be too high.


  • Pressure Valve –If the leak is originating from the pressure valve, it will be the result of high pressure. A boilers pressure should normally be between 1 and 2 bar, depending on the type of boiler it is. When this pressure has been exceeded, the pressure relief valve will leak to prevent the machine from rupturing and blowing up. Therefore it’s normal for the occasional drip, however if the leak is like a stream of a tap; the pipe has been over worked trying to relieve the excess pressure.


  • Pipe fittings – When water is discharged from around the pipe fittings, it is usually because it has been installed poorly. Here at Barry Ward, we install boilers to exceed regulations and ensure the fitting is to a high standard.


  • Boiler casing cracked or damaged – Cracks in the body of the boiler arise due to the recurring warming and cooling processes that occur. The metal casing can eventually crack from the cooling and warming procedures as metal will contract and expand. Sometimes it is more ecological to get a new appliance, as crack repairs can be costly.

This usually an easy fault to identify as splits and cracks are fairly visible.

  • Damaged seals – Impaired seals allow water to seep out, sometimes the pump will also force water through. Both the seal and the pump will have to be resealed or replaced to stop further bleeding.


As we always recommend, fix the problem sooner rather than later to eliminate it from worsening. Make sure you switch the boiler and electrical switches around the area off until the gas engineer arrives. We take great pride in what we do and get great pleasure from exceeding our clients expectations. For detailed information about our services please feel free to get in contact.

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