User manual
FILLING THE SYSTEM
1 Turn on the water main and open the
system valves.
2 Open all radiator valves.
3 Fill the system via a WRAS approved filling
loop.
4 Vent (A) any air from the boiler heat
exchanger using a suitable container to
collect any water. Ensure tube outlet (B) is
directed away from the fan or any other
electrical component to prevent any water
damage. Also place a suitable cover over
the fan to prevent any spillage of water
on to electrical connections. Ensure the
cover is removed after venting.
5 Vent all radiators, re-tighten when completed
and check the system and correct any leaks.
• The boiler integral expansion vessel is pre-
charged to 0.75 bar (equal to a static head
of 7.5m (22ft). A Schraeder type valve is
fitted to the expansion vessel to allow for
pressure adjustment if required.
• If an extra expansion vessel is fitted to the
central heating return, adjust this to the
same pressure as the appliance internal
expansion vessel, refer to separate instruc-
tions with the extra expansion vessel.
6 Briefly open the pressure relief valve to test
its operation.
7 If required increase system pressure back to
1 bar.
8 Rotate the adjustable pointer on the
pressure gauge to record the set system
pressure.
9 Isolate and remove filling loop connection to
system.
A
B
FILLING THE SYSTEM
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR 12i System/24i System
8 716 107 375b (11/05)
30
COMMISSIONING