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.
4.9.7 Pump specifications
Fig. 4.5: Pump specifications
4.9.8 Circulating pump
The circulating pump is included in the boiler. The pump
head available for the boiler is shown in Fig. 4.5.
4.9.9 System by-pass
An automatic system by-pass is included within the
boiler. The boiler is suitable for use in systems with
thermostatic radiator valves and no additional by-pass
is required.
4.9.10 Venting
The boiler is fitted with an automatic air vent. Additional
provision should be made to enable the heating system
to be vented during filling and commissioning either by
automatic air vents or manually.
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400
50
100
150
200
250
300
350
400
450
500
550
600
650
700
Volume flow [l/min]
Lift [mbar]
Pump switch in position III (pre-delivery setting)
Pump switch in position II
1500 1600 1700
Instructions for installation and servicing aquaPLUS VUI 362-712
Vessel Volume [L]
Initial system pressure (bar) 1.0 1.5
Pressure relief valve setting (bar) 3.0
Total water content of system
litres
25 2.7 3.9
50 5.4 7.8
100 10.9 15.6
125 13.6 19.5
150 16.3 23.4
175 19.1 27.3
200 21.8 31.2
225 24.5 35.1
250 27.2 39.0
275 30.0 42.9
300 32.7 46.8
325 35.7 50.7
350 38.1 54.6
375 40.9 58.5
400 43.6 62.4
425 46.3 66.3
450 49.0 70.2
475 51.8 74.1
500 54.5 78.0
For system volumes other than 0.109 0.156
those given above, multiply the
system volume by the factor across
Table 4.1: Sizing of additional expansion vessel
