Water Systems & Pipework - Bosch GREENSTAR HEATSLAVE EXTERNAL 18/25 Instruction Manual

8 716 113 389d 30/3/10 14:01
E
F
G
C
A - Appliance expansion vessel
B - Extra expansion vessel
C - Automatic bypass valve
D - Drain cock
E - Feed & expansion cistern
A
G
B
U
P
C
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR HEATSLAVE EXTERNAL 12/18-18/25-25/32
8 716 113 389d (03/2010)
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Page 11
S
1000mm min
R
T
L
R
L
L
D
F - Combined feed & expansion R - Radiators
and open vent safety pipe.
S - Static head
G - Appliance T - TRV
L - Lockshield valve U - To filling system
P - Pressure relief discharge
R
T
L
R
L
L
D
WATER SYSTEMS & PIPEWORK
IMPORTANT: The boiler should not be
allowed t o operat e wit h a ret urn
temperature of less than 40°C when the
system is up to operating temperature.
PRIMARY SYSTEM PLASTIC PIPEWORK:
• Any plastic pipework used for the CH system
must have a polymeric barrier, complying with
BS 7921 and installed to BS 5955 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
with 1000mm (minimum) length of copper or
steel pipe connected to the boiler.
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.
R
• Radiator valves should conform to
BS 2767:10.
T
• All other valves should conform to BS 1010.
L
• 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
R
installations should have TRVs fitted to
radiators within the sleeping accommodation.
T
L
• An automatic bypass valve must be connected
between the heating flow and return pipes
where TRVs are used on radiators. This must
D be fitted to give at least a 3m circuit when
activated.
• Drain cocks are required at all the lowest
points on the system.
• Air vents are required at all high points on the
system.
OPEN VENT PRIMARY SYSTEM:
• In order to comply with BS 5449 the
combined feed and vent pipe must
be connected to the BSP outlet on the
right hand side of the primary heat exchanger.
• The feed and expansion cistern (E) must be
R
positioned to provide a static head (S) of at
least 1 metre above the highest point in the
T
L heating system to the water level in the feed
and expansion cistern (E).
• No valve shall be fitted in the combined feed
and expansion and open vent pipe (F).
R
• The combined feed and expansion and open vent
pipe (F) must be at least 22mmØ.
T
SEALED PRIMARY SYSTEM:
L
• Where the system volume is more than 180
litres at 0.5 bar or exceeds 2.65 bar at
maximum heating temperature an extra
D
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 (A)
built into the appliance.
WATER SYSTEMS & PIPEWORK
11