Page 18
INSTALLATION
INSTALLATION
Boiler Size
The minimum total boiler power required is the
sum of the power required for space heating
which should be calculated in accordance with
BS EN 12831 and/or the CIBSE guide and the
power required for producing hot water which
can be read from the table to the left.
Expansion Vessel For Sealed Heating System
The table opposite can be used for sizing the
heating system expansion vessel. The water
content of the Torrent primary heat exchanger
is listed in specification tables on pages 6
and 7 and a figure 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
the table are based on a maximum boiler flow
temperature of 93°C. The expansion vessel
must be suitable to accommodate the change
in volume of water in the heating system when
heated from 10°C to 100°C, with a maximum
operating temperature of 99°C.
Feed And Expansion Tank For Open Vented
Heating System
The potential expansion of all the thermal stores
in the range is shown in the table opposite,
alongside the capacity for expansion, in our
standard F & E tank, which can be supplied as
an optional extra.
Expansion for all other open vented systems
connected to the store must be added to this
figure. So, as a preliminary assessment of the
water content of the attached open vented
systems, a figure of 4.5 l/kW of radiator output
can be used. For example, 20 kW radiator output
would have a system volume of 90 litres, and
potential expansion of this would be 3.6 litres,
and 10 kW would be 45 litres total volume and
1.8 litres for expansion.
Please refer to page 26 for further information
regarding F&E tanks when using solid fuel input.
Allowance for domestic hot water for sizing the boiler
Torrent model
Allowance for domestic
hot water heating (kW)
Full divert mode
Flow share mode
140
0
2
170
0
3
210
0
3.5
280
0
4.5
350
0
6.0
450
0
8.0
Expansion Vessel Requirements
Safety valve setting
3.0
Vessel charge
pressure (bar)
0.5
1.0
1.5
Initial system charge
pressure (bar)
0.5
1.0
1.5
2.0
1.0
1.5
2.0
1.5
2.0
Total System
Volume (litres)
Expansion Vessel Volume (litres)
25
2.1
3.5
6.5
13.7
2.7
4.7
10.3
3.9
8.3
50
4.2
7.0
12.9
27.5
5.4
9.5
20.6
7.8
16.5
75
6.3
10.5
19.4
41.3
8.2
14.2
30.9
11.7
24.8
100
8.4
14.0
25.9
55.1
10.9
19.0
41.2
15.6
33.1
125
10.4
17.5
32.4
68.3
13.6
23.7
51.5
19.5
41.3
150
12.5
21.0
38.8
82.6
16.3
28.5
61.8
23.4
49.6
Thermal Store
Potential
Expansion of
Water in Store
(litres)
Minimum Number of Feed and
Expansion Tanks
(16 litre model inc. 10 litre expansion)
TEC140
OV model - 6.6
SP model - 6.6
1
TEC170
OV model - 7.0
SP model - 7.0
1
TEC210
OV model - 9.6
SP model - 9.5
SOL model - 8.0
1
TEC250
OV model - 10.6
SP model - 10.1
SOL model - 11.1
2
TEC350
OV model - 16.5
SP model - 16.3
SOL model - 16.4
2
TEC450
SOL model - 21
3
Expansion of all connected open vented systems must be added to the store
expansion when choosing the size of the feed and expansion tank.
The weight of each tank when full is 27kg (not including pipework and valves).
