WATER SYSTEMS & PIPEWORK
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER BOSCH GREENSTAR 12i System/24i System
8 716 107 375a (02/05)
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WATER SYSTEMS & PIPEWORK
PLASTIC PI PEWOR K & U N DE R FLOOR
HEATING:
• Any plastic pipework must have a polymeric
barrier with 600mm (minimum) length of
copper or steel pipe connected to the boiler.
• Plastic pipework used for underfloor heating
must be correctly controlled with a
thermostatic blending valve limiting the
temperature of the circuits to approx. 50°C.
CONNECTIONS/VALVES:
• All system connections, taps and mixing
valves must be capable of sustaining a
pressure up to 3 bar.
• Radiator valves should conform to
BS2767:10.
• All other valves should conform to BS1010.
• On new installations TRV’s must be used on
all radiators except where a room thermostat
is sited. On all installations they should at
least be fitted in the sleeping areas. See note
below on open radiator/bypass
• A drain cock is required at the lowest point
on the system.
• An air vent is required at the highest point on
the system.
S and Y PLAN SYSTEM:
• NB The boiler is fitted with its own internal
bypass.
A Diverter Valve
B Radiator Valve (Flow)
C Lockshield Valve (Return)
• NB A drain cock should be fitted at the
lowest point of the heating circuit and
beneath the appliance.
OPTIONAL INTERNAL DIVERTER VALVE:
This boiler is designed to operate on a sealed
system only. The boiler will require a second
return pipe from the water cylinder to the wall
mounting frame and terminate in 15mm copper
pipe.
• The CH sealed system must be filled using a
WRAS approved filling loop or comply with
the diagram opposite for system fill.
• Where the system volume is more than 100
litres or exceeds 2.65 bar at maximum
heating temperature, an extra expansion
vessel (B) must be fitted as close as possible
to the appliance in the central heating return.
• Pressurise the extra expansion vessel (B) to
the same figure as the expansion vessel built
into the appliance.
•
Do not use galvanised pipes or radiators.
WITH EXTERNAL DIVERTER VALVE
Boiler flow
Return from
cylinder
Return from
central heating
WITH OPTIONAL INTERNAL DIVERTER VALVE FITTED
(NOT SUPPLIED WITH BOILER)
A
B
