Boiler Pressure Drop

[ForgedPlane]

We have a 15 month old Worcester Greenstar 4000 which was serviced last month. We have recently been experiencing intermittent pressure drops on the system and are having to top the system up to get the boiler to kick in. The pressure drops are not consistent - for example, last weekend we didn't have any drops for 3 days and then it dropped from 1.1 bar to 0.2 bar overnight on the Monday. The installer has been out to check the PRV valve and internal expansion vessel and they don't seem to have any faults. He has said that the most likely reason for pressure dropping now is a leak somewhere in the system, although there is nothing visible, and has suggested adding some Fernox Express Leak Sealer to the system as a next step (either that or calling out a professional leak detection person but clearly far more expensive!) in the hope that this fixes the issue. However, my question is - if there were a leak somewhere in the system, wouldn't the pressure be dropping more consistently? It's boggling my brain that we could not see a pressure drop for days and then suddenly see a huge drop! Any ideas?

[Funkyboy]

Did you ever get to the bottom of this? I've got same boiler and having similar issues but not such big drops as you.

Thanks

[Someone-Else]

ForgedPlane asked the ONE question in December and has never posted since. (Which is now 3 months ago) so I doubt he will reply to you. It's bad forum etiquette to reply to old posts for this reason, I would suggest you start your own thread