My girlfriend just had a combi boiler installed.
She used to have a conventional heating system with an expansion tank in the loft, but the new system is sealed with an expansion vessel in the boiler unit.
I know that the system is filled by a flexible hose between the mains cold water feed and the central heating circuit, but how on earth does inhibitor get added to a system like this?
When the system was installed we had to bleed a large amount of air out of several radiators. Without an expansion tank and the usual supply of cold water into the system when needed, how does the system stay topped up? Do I have to open the feed from cold water supply to ensure the system stays full?