How to refill Ariston combi?

My friend has just installed a new Flow Swith in his Ariston MicroGenius 23, however there now isn't enough water pressure for the system to start working. There are several pipes out of the bottom of the boiler; so far I have identified the valve that supplies the hot tap but not much else! From memory there are 5 or 6 valves along the bottom of the boiler, but none of these seems to refill the system. Do I need to be operating a couple of valves together? Or am I looking in the wrong place?

Sorry this is such a basic question, but my knowledge of refilling only extends to my own combi boiler, which involves turning a single valve.

Thanks in advance for any help.

could this involve a 'fill loop' that's concealed? I notice all the pipes extend below the counter top, behind the washing machine... in which case, is this a simple tap that needs turning?

yes either concealed or removed as it should be keep looking for a service valve with a pipe hanging from it will be there somewhere well fingers crossed

Found it! two little valves on a short flexi-pipe, tucked right round the back of all the pipes. Now have slightly scraped knuckles but lots of heat! Thanks.