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INDUSTRIE
Built-in Central Heating Water Circulating Pump
The pump head available for circulating the water is given in fig. 8.
N.B. - The pump is factory set at position 3. The pump is a Grundfos type 25-50 UPS series.
Note - Minimum flow through boiler heat exchanger at any time should not fall below 6 litres per minute.
If the total volume of water in the system exceeds 40 litres an additional expansion vessel must be fitted
to the central heating return inlet.
Pump performance curve Grundfos UPS 25-50
SAFETY VALVE
SETTING (bar)
VESSEL CHARGE
PRESSURE (bar)
INITIAL SYSTEM
1.0
PRESSURE (bar)
TOTAL WATER
EXPANSION VESSEL VOLUME (litres)
CONTENT of SYSTEM
LITRES
25
3.5
50
7.0
12.9
75
10.5
19.4
100
14.0
25.9
125
17.5
32.4
150
21.0
38.8
175
24.5
45.3
200
28.0
51.8
For syst. volumes other than
those given above, mult. the syst.
0.140
0.259
volume by the factor across
12
3.0
0.5
1.0
1.5
2.0
1.5
2.0
6.5
13.7
4.7
10.3
27.5
9.5
20.6
41.3
14.2
30.9
55.1
19.0
41.2
68.9
23.7
51.5
82.6
28.5
61.8
96.4
33.2
72.1
110.2
38.0
82.4
0.551
0.190
0.412
1 2 3 Speed settings
A Boiler pressure drop
B Max. available pump head C.H.
Fig. 8
SIZING OF ADDITIONAL EXPANSION VESSELS:
Deduct from the value given in the table the 7 litre
1.5
vessel supplied.
2.0
Note
1. Fill C.H. installation to min. 1.5 bar.
2. Select by preference the expansion vessel for
8.3
increased system pressure of 2.0 bar
16.5
24.8
3. Expansion vessel must be fitted to Central
33.1
Heating Return Inlet
41.3
4. The standard 7 litres expansion vessel is charged
49.6
57.9
to 1 bar
66.2
0.33
Fig. 9
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