WATER SYSTEMS & PIPEWORK
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR DANESMOOR UTILITY 18/25
8 716 106 256C (03/2010)
11
P
R
E -
IN
ST
AL
LA
TI
O
N
R
TYPICAL OPEN VENT SYSTEM:
A - Appliance.
B - Expansion vessel.
C - Automatic bypass valve.
D - Drain cock.
E - Feed and expansion cistern.
F - Feed and expansion
15mmØ min.
G - Pressure gauge.
H - Open 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 - Thermostatic radiator
valve (TRV).
U - To filling system.
E
1000mm min.
F
H
A
R
R
R
R
D
C
T
L
T
L
T
L
L
L
J
K
M
150mm max.
K
TYPICAL SEALED SYSTEM:
A
D
R
R
R
B
P
D
C
T
L
T
L
T
L
L
L
G
J
K
M
N
D
U
S
WATER SYSTEMS & PIPEWORK
PRIMARY SYSTEM PLASTIC PIPEWORK:
• Any plastic pipework used must have a
polymeric barrier, comply with BS 7921and
be 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.
• Radiator valves should conform to
BS 2767:10.
• All other valves should conform to BS 1010.
• 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 TRVs fitted to
radiators within the sleeping accommodation.
• An automatic bypass valve must be connected
between the heating flow and return where
TRVs are used on all radiators, fitted to give
at least a 3 metre 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:
• The open vent pipe (H) and feed and
expansion pipe (F) 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
(H) or the feed and expansion pipe (F).
• The open vent pipe (H) must be at least
22mmØ.
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 boiler or onto one of the boiler
top 1” BSP outlets.
• An expansion vessel (B) must be fitted to the
heating return pipe as close as possible to
the boiler 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
boiler 1” BSP outlets.
• An automatic air vent (N) must be fitted.
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.
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