Why is my combi boiler losing pressure if there’s no leak?

There are a number of reasons why a boiler could lose pressure. Here are some of the most common:

• There’s a leak – Although you might not have located a leak in your heating system yet, it is one of the most likely causes. It might not be obvious so we recommend hiring a boiler engineer to thoroughly check your boiler and heating system
• Boiler needs to be re-pressurised – Over time, boilers will naturally lose pressure slowly. If that’s the case, you simply need to re-pressurise the boiler
• Air pockets in radiators – If any air has built up in your radiators, it can cause a drop in boiler pressure. If that’s happened in your home, you simply need to bleed your radiators
• Faulty pressure release valve – The pressure release valve helps control the pressure in your heating system. If the valve is faulty, it could cause your boiler to lose pressure
• Faulty pressure gauge – This is an uncommon issue, but could be extremely dangerous. If you have reason to believe that your pressure gauge is faulty, contact a local boiler engineer immediately

If your boiler is losing pressure, we would always recommend speaking to an experienced local boiler engineer. A qualified professional tradesperson will be able to identify the issue and remedy the problem.

Want to know more? Check out our guide to common boiler faults.

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