How to Top Up Your Worcester 4000 Boiler Using the Keyless Filling LinkIf your Worcester 4000 boiler is showing low pressure, topping it up is simple thanks to the built-in keyless filling link. This guide explains everything homeowners need to safely restore boiler pressure and keep their heating system running efficiently.Quick Guide: Top Up Worcester 4000 Boiler PressureFollow these steps to safely top up your Worcester 4000 boiler: Keep the boiler on so the digital display shows the curre...