Worcester 50/70 Installation And Servicing Instructions page 9

Fig. 8. Typical Open Vent Gravity Primary System.
Feed and
Vent Cistern
Primary cold
feed (15mm min.)
Domestic
hot water
cylinder
Fig. 9. Typical Open Vent Fully Pumped System (Honeywell 'Y' plan).
Feed and
Vent Cistern
Primary cold
feed (15mm min.)
Heating vent
(22mm min.)
S.H.
Pump
Boiler
Heating vent
(22mm min.)
Domestic hot
S.H.
water cylinder
Diverting
valve
Pump
Boiler
9
S.H. – Minimum static head 1m (3ft)
measured from the top surface of the
S.H.
appliance or highest point in the
heating system to the water level in
the feed and expansion tank
N.B. A drain cock should be
installed at the lowest point
of the heating circuit
Radiator
S.H. – Minimum static head 1m (3ft)
measured from the top surface of the
S.H.
appliance or highest point in the
heating system to the water level in
the feed and expansion tank
N.B. A drain cock should be
installed at the lowest point
of the heating circuit
Radiator