Water Systems & Pipework - Worcester 440CDi Instruction Manual

TYPICAL SEALED SYSTEM:
A
B
P
C
A - Appliance expansion vessel
B - Extra expansion vessel
C - Automatic bypass valve
D - Drain cock
L - Lockshield valve
P - Pressure relief discharge
R - Radiators
T - TRV
INSTALLATION & SERVICING INSTRUCTIONS
8 716 115 219b (09.2008)
R R
T
T
L
R R
T T
L
D
WATER SYSTEMS & PIPEWORK
PRIMARY SYSTEM PLASTIC PIPEWORK:
• Any plastic pipework must have a polymeric
barrier with 600mm (minimum) length of
copper 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.
The pipework from the boiler to the
blending valve must be in copper.
PRIMARY
SYSTEM/CONNECTIONS/VALVES:
• Do not use galvanised pipes or radiators.
• All system connections, taps and mixing
valves must be capable of sustaining a
pressure of 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 the radiator where
the room thermostat is sited, this must be
fitted with lockshield valves and left open.
All installations should have TRV's fitted
to radiators within the sleeping
accommodation.
• Drain cocks are required at all the lowest
points on the system.
• Air vents are required at all high points on
the system.
SEALED PRIMARY SYSTEM:
• Where the system volume is more than
L
100 litres or exceeds 2.5bar 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
L
built into the appliance - REFER TO
TECHNICAL DATA TABLE.
D
WATER SYSTEMS & PIPEWORK
9