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Staying in my daughter's flat and she said she had a problem with her boiler- leaking. Looks like it was just a leaky joint in the pipework just above the boiler, tightened it up looks ok at the mo.
In my research (I'm not a plumber) I noticed that this boiler is fitted with an internal expansion tank. However, there is also a large external expansion tank showing only 0.25 bar right next to the boiler and connected by pipework to it. Don't understand. Please advise. And do I need to recharge either or both of these expansion tanks as a result of the leak.
I can see no other discernable need for the external expansion tank as there is no other form of heating on this modern flat.

Hi psimmo,
Yes you must top up the pressure in the system it needs to be 1-2 bar — look at the pressure gauge it should show the maximum.
The problem with expansion vessels inside the boiler casing is that - in theory at least - if it fails a Gassafe plumber is needed. It’s more economic to fit an external pressure vessel which can be bigger than the boiler one.
Regards S