Boiler losing pressure but can’t find leak!!

22 Mar 2022
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United Kingdom

We’ve had an issue with the boiler losing pressure that needs refilling once a week. We’ve had 3 different leak detection companies and they could never find a leak. We’ve had multiple boiler engineers and they can never find an issue with the boiler.

Recently, a gas engineer suggested isolating the radiators to help confirm that the leak is coming from the radiator pipes and allow the hot water to function. However, a week later the pressure gauge didn’t drop but the fault code showed up on our combi boiler indicating the pressure had dropped. He has been waiting to hear back from the manufacturers over the last few days with no answer yet to explain what’s happening with the boiler, how to clearly identify the problem and provide a solution.

Our last resort is to lift all the wood flooring in the downstairs living room and kitchen to visibly look for a leak. However, this has its own issues and we would like to avoid if we don’t need to do it.

Any suggestions on why the pressure dropped when the radiators were isolated? Any ideas on what would be the overall issue and what the best solution would be going forward?

Thank you so much in advance!!
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Why don’t you pour a bottle of old fragrance in when you fill it back up and sniff it out?
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turn boiler off and disconnect the condensate pipe and leave a bowl under it see if you get any water in it, do not use the boiler while testing
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Reactions: CBW
How long have you had this problem?
Is it getting worse? Is it getting better?
What is the system pressure after turning the boiler OFF for an hour?
What is the pressure after the heating has been ON for an hour?

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