Worcester WM 12 Installation And Servicing Instructions page 13

Fig. 13. Typical fully pumped sealed system (Honeywell 'Y' plan).
Boiler
To system filling device (see fig.14)
Fig. 14. System filling and make-up
Worcester combi-fill system
Heating
return
Non return Non return
valve valve
Test cock
METHOD 1
Automatic
air vent
Domestic hot
water
cylinder
Pressure
Safety valve
gauge
Expansion
Vessel
Hose union
Stop cock
Temporary
hose
Diverting
valve
Pump
Auto air
vent
Heating
return
13
N.B. A drain cock should be
installed at the lowest point of
the heating circuit
Radiator
Make up
vessel
Non return
valve
30mm (12in) min.
above highest
point of the system
Stop
cock
Fill point.
Heating return
METHOD 2