two options here i think ? the first option is the easiest on the water inlet pipe (cold water in) there should be a joint or a flexible pipe and directly opposit that on the thicker pipe usually 22mm (return flow pipe ) there should be another joint connect these pipes together and turn the tap slowly and very carefully allow water into the boiler however if its the other type you need a large key like device and a black nut type device go under the boiler and pull off the metal cover it just pulls of on the right side of the boiler insert the lage key and turn it clockwise half turn then get the small black nut like device and next to the key device there should be a smaall square bolt type thing turn the nut clockwise also and you should hear water going into boiler if its that way to fill the boiler then i would be very surprised if the engineer left it with you ? hopefully one of those works for you
mark brooke, October 2007