Technical data

Installation and servicing instructions for wall-mounted condensing gas boiler Buderus 600 - 11R/19R/24R • 02/2006 11
Subject to modifications resulting from technical improvements! Buderus • http://www.buderus-domestic.co.uk
8. Filling
The system may be filled through a temporary hose
connection from a draw-off tap supplied from a servicing
pipe under mains pressure. Where the mains pressure
is excessive a pressure reducing valve shall be used to
facilitate filling.
The following fittings shall form a permanent part of the
system and shall be fitted in the order stated:
– A stop valve complying with the requirements of
BS. 1010, Part 2 (the hose from the draw-off tap
shall be connected to this fitting);
– A test cock;
– A double check valve of an approved type.
Sizing procedure for expansion vessel
The volume of the expansion vessel (litres) fitted to a
sealed system shall not be less than that given by
table 1, multiplied by a factor of 0.8 (for flow tempera-
tures of less than 80 °C).
Safety valve setting 3.0 bar
Vessel charge and
initial system pressure
0.5 1.0 1.5
bar bar bar
Total water content of
system (litres)
Expansion vessel
volume litres
25 2.1 2.7 3.9
50 4.2 5.4 7.8
75 6.3 8.2 11.7
100 8.3 10.9 15.6
125 10.4 13.6 19.5
150 12.5 16.3 23.4
175 14.6 19.1 27.3
200 16.7 21.8 31.2
225 18.7 24.5 35.1
250 20.8 27.2 39.0
275 22.9 30.0 42.9
300 25.0 32.7 46.8
Multiplying factors for
other system volumes
0.0833 0.109 0.156
Table 1 Expansion vessel volumes