Bosch Worcester Greenstar Utility 32/50 Installation, Commissioning And Servicing Instruction Manual page 12

Pre-Installation
Open vent primary system
• The open vent pipe [F] and feed and expansion pipe [H] must rise
continuously from the appliance.
• The feed and expansion cistern [E] must be positioned to provide a
static head [S] of at least 1 metre above the highest point in the
heating system to the water level in the feed and expansion cistern
[E].
• Ensure adequate space is left in the expansion cistern for expansion
of the system water.
• No valve shall be fitted in the open vent pipe [F] or the feed and
expansion pipe [H].
• The open vent pipe [F] must be at least 22mmØ.
Fig. 7 Typical open vent system
12
Fully pumped sealed primary system:
• A pressure relief valve [P], spring loaded safety valve set to operate
at 3bar, must be fitted to the heating flow pipe as close as possible to
the appliance or onto one of the appliance top 1¼ " BSP outlets.
• An expansion vessel [B] must be fitted to the heating return pipe as
close as possible to the appliance and pressurised for the system
volume according to the instructions supplied with the vessel.
• A pressure gauge [G], 3 bar minimum, must be fitted to the heating
flow pipe or one of the appliance 1¼ " BSP outlets.
• An automatic air vent [N] must be fitted.
Fig. 8
[A]
[B]
[C]
[D]
6720808218-07.1Wo
[E]
[F]
[G]
[H]
[J]
[K]
[L]
[M]
[N]
[P]
[R]
[S]
[T]
[U]
Filling primary sealed systems
• Filling the system must comply with one of the methods shown in the
figure below.
• The filling point must be at low level and must never be a permanent
direct fixing to the mains water supply.
• Filling links must be WRAS approved.
Fig. 9
[SV] Stop valve
[CV] Check valve
K1
Typical sealed system
Appliance
Expansion vessel
Automatic bypass valve
Drain cock
Feed and expansion cistern
Open vent 22mmØ min.
Pressure gauge
Feed and expansion 15mmØ min.
Circulating pump
Zone valves
Lockshield valve
Hot water cylinder
Automatic air vent
Pressure relief discharge
Radiators
Static head
Thermostatic radiator valve (TRV)
To filling system
SYSTEM FILL
Heating
return
Hose union
SV
Temporary hose
Greenstar Utility
6720808218-08.1Wo
Mains
supply
CV CV
SV
Test point
ErP - 6 720 821 751 (2018/04)