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INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER BOSCH
8-716-109-711a (04.05)
PLASTIC PIPEWORK:
Any plastic pipework must have a polymeric
barrier with 1000mm (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. The pipework from the
boiler to the blending valve must be in copper
or steel (protected from corrosion).
Do not use plastic pipework on sealed
systems.
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 up to
3 bar
Radiator valves should conform to BS2767:10
All other valves should conform to BS1010
On new installations TRVs 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
An automatic bypass valve must be connected
between the heating flow and return where TRV's
are used on all radiators
Drain cocks are required at all the lowest points
on the system
Air vents are required at all the high points on
the system.
OPEN VENT PRIMARY SYSTEM:
The cold feed (F) and expansion tank (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 expansion
tank (E)
The heating vent (H) and cold feed (F) pipes
must rise continuously from the appliance.
The heating vent pipe (H) must be at least
22mmØ and 350mm above the waterline in the
cold feed and expansion tank (E).
FULLY PUMPED SEALED PRIMARY SYSTEM:
A pressure relief valve (P) (spring loaded safety
valve set to operate at 3 bar) must be fitted to
the heating flow pipe as close as possible to
the boiler
An expansion vessel (B) should be fitted to the
heating return pipe close to the boiler and
pressurised for the system volume according to
the instructions supplied with the vessel
A pressure gauge (G) (3 bar min.) must be fitted
to the heating flow pipe
An automatic air vent (N) must be fitted.
9
WATER SYSTEMS & PIPEWORK
WATER SYSTEMS & PIPEWORK
TYPICAL OPEN VENT SYSTEM:
S
350mm min.
1000mm min.
F
H
150mm max.
E
A
D
R
R
R
R
D
C
T
T
L
T
L
J
K
M
K
L
T
L
A - appliance
B - expansion vessel
C - automatic bypass valve
D - drain cock
E - expansion tank
F - cold feed 15mmØ min
G - pressure gauge
H - heating vent 22mmØ min
J - circulating pump
K - zone valve
L - lockshield valve
M - hot water cylinder
N - automatic air vent
P - pressure relief discharge
R - radiators
S - static head
T - TRV
U - to filling system
TYPICAL SEALED SYSTEM:
A
D
B
P
D
C
T
L
T
L
T
L
T
L
G
J
K
M
N
U
R
R
R
R
