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Why is my boiler leaking?

A leak from your boiler can be due to a range of problems and are fairly common to boilers in many households. It is important to remember that a leak should be fixed as soon as possible to avoid the leak becoming worse. A failure to fix the problem can also lead to corrosion of the boiler’s internal parts and minor flooding. You should never carry out any repairs or servicing on the system yourself; this needs to be done by a qualified boiler and heating engineer.

Below we have set out some of the common causes for a leaking boiler that you should look out for:-

Leak from temperature and pressure relief valve

If the leak is coming from here, it is either because the boiler is heating the water too much or because the boiler has too much water pressure in it. You should check the temperature and pressure gauge on the boiler. The pressure should be between 18-21 psi and the temperature between 180-240 degrees. The relief valve is designed discharge water in the boiler when it gets too high as a safety measure. Therefore, if the pressure is around 28-30 psi, chances are this is what has happened.

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If the pressure in the boiler is too high, the cause could be the water feed regulator. This is a small brass device on the water line which supplies fresh water to the boiler. If the boiler is discharging from the relief valve due to the temperature being too high, you may want to try turning down the temperature dial on the boiler. If this doesn’t have any success, the temperature probe could be faulty.

Leak from heat exchanger

There are usually three things that can make a boiler leak from the heat exchanger. The first one isn’t really the result of a leak, but condensation which can occur on this part of the boiler when it has been heated from cold. However, if it appears to be something more serious then it could be being caused by a fitting or a connection. If it’s a mechanical fitting it might only need to be replaced, or tightened. However, certain components in boilers are prone to failing due to thermal shock (i.e. excessive expansion or contraction) due to being repeatedly heated and cooled. Failing a problem of that nature it is more than likely that you have a crack or a failure in the heat exchanger itself. This can be caused by wear and tear (age), corrosion or physical damage. Sometimes these sorts of cracks can be repaired but you will need to contact us in order for an appropriately qualified heating engineer to assess the damage and see if the heat exchanger can be repaired or if it needs to be fully replaced.

Crack in the boiler’s cast iron or aluminium sections

In most situations, this is a major fix and can be very expensive. Sometimes it may be a better alternative to have your boiler replaced, but this will depend on the size of the crack and how old the boiler is. If you think that there is a crack in your boiler then you should contact us immediately so that we can come and inspect the boiler and assess the work that needs to be carried out.

If you are in any doubt whatsoever please contact us at our 24 hour call centre on 0844 272 0941