Expansion Vessel; Pump Specifications; Circulating Pump; System By-Pass - Vaillant aquaPlus Instructions For Installation And Servicing

4 General Requirements

4.9.6 Expansion vessel

The aquaPLUS incorporates a 10 litre expansion vessel
which is suitable for a sealed heating system with a
maximum water content of 100 litres.
If the nominal capacity of the built in expansion vessel is
not sufficient for the heating system (for instance in
case of modernization of old open systems) an
additional expansion vessel can be installed external to
the boiler. It should be fitted in the return pipe as close
as possible to the boiler in accordance with BS 5449:
Part 1.
Guidance on the sizing of an additional expansion vessel
is given in Table 4.1.
Initial system pressure (bar)
Pressure relief valve setting (bar)
Total water content of system
litres
25
50
100
125
150
175
200
225
250
275
300
325
350
375
400
425
450
475
500
For system volumes other than
those given above, multiply the
system volume by the factor across
Table 4.1: Sizing of additional expansion vessel
12
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4.9.7 Pump specifications

Vessel Volume [L]
1.0 1.5
3.0 Fig. 4.5: Pump specifications

4.9.8 Circulating pump

The circulating pump is included in the boiler. The pump
2.7 3.9
head available for the boiler is shown in Fig. 4.5.
5.4 7.8
10.9 15.6

4.9.9 System by-pass

13.6 19.5
An automatic system by-pass is included within the
16.3 23.4
boiler. The boiler is suitable for use in systems with
thermostatic radiator valves and no additional by-pass
19.1 27.3
is required.
21.8 31.2
24.5 35.1
27.2 39.0

4.9.10 Venting

30.0 42.9 The boiler is fitted with an automatic air vent. Additional
provision should be made to enable the heating system
32.7 46.8
to be vented during filling and commissioning either by
35.7 50.7
automatic air vents or manually.
38.1 54.6
40.9 58.5
43.6 62.4
46.3 66.3
49.0 70.2
51.8 74.1
54.5 78.0
0.109 0.156
700
650
600
550
500
450
400
350
300
Pump switch in position III (pre-delivery setting)
250
200
150
Pump switch in position II
100
50
0 100 200 300 400 500 600 700 800
Instructions for installation and servicing aquaPLUS VUI 362-7
900 1000 1100 1200 1300 1400 1500 1600 1700
Volume flow [l/min]