gledhill BoilerMate BP Installation & Service Manual page 14

DESIGN
Heating System
Open Vented Heating Systems
The layout of a typical open vented 'Y Plan' heating system is shown in fi gure 8. The
BoilerMate BP is equally suitable for 'S' and 'W' plan heating system layouts.
The fl ow pipe from the boiler should rise continuously up to the vent pipe to facilitate
venting. The heating circuit is taken directly from the boiler and is piped in the
conventional manner.
The F & E cistern supplied with the thermal store can be fi tted remotely up to 6m above
the base of the BoilerMate BP. If this cistern is used for the central heating as shown
in fi gure 8, then the water level in the F&E cistern should be at least 250mm above
the highest point on the system including the radiators and must be high enough to
provide the minimum head required by the boiler being used.
Sealed Heating Systems
The layout of a typical sealed 'Y Plan' heating system is shown in fi gure 9. The BoilerMate
BP is equally suitable for 'S' and 'W' plan heating system layouts. A boiler used in a
sealed heating system must be suitable for this application i.e. must be fi tted with an
overheat cut-out thermostat.
It is recommended that the F&E cistern (for the store) is fi tted at a high level in the
same cupboard as the BoilerMate BP. However it can be fi tted remotely up to 6m
above the base of the BoilerMate BP.
The F&E cistern overfl ow/warning pipe should be installed in a material suitable for a
heating system feed and expansion cistern in accordance with BS5449.
There shall be no permanent connection to the mains water supply for fi lling the
system even through a non-return valve without the approval of the Local Water
Authority. An approved fi lling loop is required with for fi lling the system, which should
be disconnected after commissioning the system. This should be located adjacent to
the boiler along with a suitable expansion vessel, pressure gauge, pressure relief valve.
The table below can be used for sizing the heating system expansion vessel. The
water content of the primary heat exchanger is listed in table 1 and a fi gure of 4.5
l/kW of installed radiator capacity can be used for a preliminary assessment of the
water content of the heating system.
The expansion vessel requirements shown in table below are based on a maximum
Expansion Vessel Requirements
Safety valve setting
(bar)
Vessel charge
pressure (bar)
Initial system
0.5
pressure (bar)
Total System
Volume (l)
25 2.1
50 4.2
75 6.3
100 8.4
125 10.4
150 12.5
SYSTEM DETAILS
3.0
0.5 1.0
1.0 1.5 2.0 1.0 1.5
Expansion Vessel Volume (l)
3.5 6.5 13.7 2.7 4.7
7.0 12.9 27.5 5.4 9.5
10.5 19.4 41.3 8.2 14.2 30.9 11.7 24.8
14.0 25.9 55.1 10.9 19.0 41.2 15.6 33.1
17.5 32.4 68.9 13.6 23.7 51.5 19.5 41.3
21.0 38.8 82.6 16.3 28.5 61.8 23.4 49.6
boiler fl ow temperature of 93°C. The expansion
vessel must be suitable to accommodate the
change in volume of the water in the system
when heated from 10°C to 110°C a sspecifi ed
in BS 5449:1990clause 16.2.
The minimum system pressure should not be
less than the static head plus 0.5bar i.e. the
height of the highest point in the system above
the expansion vessel plus a margin of 0.5 bar.
1.5
2.0 1.5 2.0
10.3 3.9 8.3
20.6 7.8 16.5
Page 14