Buderus 600 - 11R Installation And Servicing Instructions page 10

Sealed system requirements
1. General
The installation must comply with the requirements of
BS. 6798 and BS. 5449.
All components of the system, including the heat
exchanger of the indirect cylinder, must be suitable for a
working pressure of 3 bar and temperature of 110 °C.
Care should be taken in making all connections so that
the risk of leakage is minimised.\
2. Safety valve
A spring loaded safety valve complying with the relevant
requirements of BS. 6759 must be fitted in the flow pipe
as close to the boiler as possible and with no intervening
valve or restriction. The valve should have the following
features:
– A non-adjustable preset lift pressure not exceeding
3 bar;
– A manual testing device;
– Provision for connection of a discharge pipe. The
valve or discharge pipe should be positioned so that
the discharge of water or steam cannot create a
hazard to the occupants of the premises or cause
damage to electrical components and wiring.
SYSTEM FILL
Heating return
Non return
Hose
return
Stop
cock
T emporar y hose
SYSTEM MAKE UP
Heating return Auto
air vent
Non
return valve
Stop
valve
Fill point
fig. 7 System fill and make up
3. Pressure gauge
A pressure gauge covering at least the range of 0-4 bar
must be fitted to the system. The gauge should be easily
seen from the filling point and should preferably be
connected at the same point as the expansion vessel.
Buderus • http://www.buderus-domestic.co.uk
10 Installation and servicing instructions for wall-mounted condensing gas boiler Buderus 600 - 11R/19R/24R • 02/2006
Non return
valve valve
Mains
supply
Stop coc k
T est coc k
Make up
vessel
1000 mm
above the
highest point of
the system
4. Expansion vessel
A diaphragm type expansion vessel must be connected
to a point close to the inlet side of the pump, the
connecting pipe being not less than 15 mm size and not
incorporating valves of any sort.
The vessel capacity must be adequate to accept the
expansion of the system water when heated to 110 °C.
The charge pressure must not be less than the static
water head above the vessel. The pressure attained in
the system when heated to 110 °C should be at least
0.35 bar less than the lift pressure of the safety valve.
For guidance on vessel sizing refer to table 1.
For further details refer to BS. 5449 and BS. 7074:1 and
the British Gas Corporation publication: "Material and
Installation Specifications for Domestic Central Heating
and Hot Water".
5. Cylinder
The cylinder must be either of the indirect coil type or a
direct cylinder fitted with an immersion calorifier which is
suitable for operating on a gauge of 0.35 bar in excess
of the safety valve setting. Primatic cylinders are not
suitable for sealed systems.
6. Make-up water
provision must be made for replacing water loss from the
system, either:
– from a manually filled make-up vessel with a readily
visible water level. The vessel should be mounted at
least 150 mm above the highest point of the system,
and be connected through a non-return valve to the
system, filled at least 300 mm below the make-up
vessel on the return side of the domestic hot water
cylinder or radiators.
or
– where access to a make-up vessel would be difficult
by pre-pressurisation of the system. Refer to "Filling",
below.
7. Mains Connection
There must be no direct connection to the mains water
supply or to the water storage tank supplying domestic
water, even through a non-return valve, without the
approval of the local water authority.
Subject to modifications resulting from technical improvements!