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Technical Data - Page 9
Boiler Heat Exchanger:
Small Bore Pipework:
Micro Bore Pipework:
Steel Panel Radiators:
Low Water Capacity Radiators:
Hot water Cylinder:
If the system is extended, the expansion vessel volume
may have to be increased unless previous provision has
been made for the extension. Where a vessel of the
calculated size is not available, the next available larger
size should be used. The boiler flow temperature is
controlled at approximately 82ºC.
The vessel size can now be determined from the following
table where V=System volume in litres.
Vessel Charge Pressure (bar)
Initial System Pressure (bar)
Expansion Vessel Volume (litres)
Further guidance is given in BS 5449 Part 1 or BS 7074
Part 1.
FIG. 6 OPEN VENTED FULLY PUMPED SYSTEM
FITTED WITH A COMBINED FEED AND VENT
Supplied By www.heating spares.co Tel. 0161 620 6677
6.5 litres
1 litre per kW of
system output
7 litres
8 litres per kW of
system output
2 litres per kW of
system ouput
2 litres
0.5
1.0
1.0
1.0
Vx0.11
Vx0.087
9
Cylinder
The hot water cylinder must be an indirect coil type or a
direct cylinder fitted with an immersion calorifier
suitable for operating at a gauge pressure of 0.3 bar
2
(5lbf/in
) in excess of safety valve setting. Single feed
indirect cylinder are not suitable for sealed systems.
Method of Make-Up
Provision shall be made for replacing water loss
from the system either:-
i)
from a make-up vessel or tank mounted in a
position higher than the top point of the system,
and connected through a non-return valve to the
system on the return side of hot water cylinder
or the return side of all heat emitters.
or
ii)
where access to a make-up vessel would be
difficult by using the mains top up method or
a remote automatic pressurisation and make-up
unit as sillustrated in FIG. 7 METHODS 1 and 2.
Mains Connection
There shall be no connection to the mains water
supply or to the water storage tank which supplies
domestic water even through a non-return valve,
without the approval of the local Water Authority.
Filling Point
The system shall be fitted with a filling point at low
level which incorporates a stop valve to BS1010
and a double check valve (approved by the National
Water Council) to be fitted in this order from the
system mains, Refer to FIG. 7. Method 1.
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