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The expansion vessel is preloaded with pressurised air through the valve
accessible from the special maintenance compartment (Fig.1, Face F).
The preload value with which the expansion vessel is supplied by the man-
ufacturer is in agreement with the parameters SP and RP set as default,
and anyway it satisfies the following equation:
Pair = SP – RP – 0.7 bar
So, by the manufacturer:
If different values are set for the parameters SP and/or RP, regulate the
valve of the expansion vessel releasing or letting in air until the above
equation is satisfied again (e.g.: SP=2.0bar; RP=0.3bar; release air from
the expansion vessel until a pressure of 1.0 bar is reached on the valve).
Failure to respect the above equation may lead to malfunctions
of the system or to premature breakage of the diaphragm inside
the expansion vessel.
Considering the expansion vessel capacity of only 1 litres, any
operation to check the air pressure must be performed by con-
necting the pressure gauge very rapidly: on small volumes the
loss of even a limited quantity of air can cause an appreciable
drop in pressure. The quality of the expansion vessel ensures
the maintenance of the set air pressure value, proceed to check
it only at calibration or if you are sure of a malfunction.
Any operation to check and/or reset the air pressure must be
performed with the delivery system not under pressure: discon-
nect the pump from the power supply and open the utility nearest
to the pump, keeping it open until it no longer gives any water.
The special structure of the expansion vessel ensures its quan-
tity and duration over time, especially of the diaphragm which
is typically the component subject to wear for items of this type.
However, in the case of breakage, the entire expansion vessel
must be replaced and exclusively by authorised personnel.
43
Where:
- Pair = air pressure value in bar
- SP = Set Point (par. 5.3.1) in bar
- RP = Reduction of pressure to restart
(par. 5.5.1) in bar
Pair = 3.0 – 0.3 – 0.7 = 2.0 bar
1.3 Integrated electropump
The system has a built-in centrifugal electropump of the multi-impeller type
driven by a water-cooled three-phase electric motor. Cooling of the motor
with water rather than air ensures less noise in the system and the possibil-
ity of locating it even in recesses without ventilation.
The graph in Fig.6 shows the curve of the hydraulic performance.
By automatically modulating the rotation speed of the electropump, the
inverter allows it to shift its work point according to necessities to any part
of the area subtended by its curve, to keep the set pressure valve constant
(SP). The red curve shows the behaviour of the e.sybox mini with set point
at 3.0 bar.
Figure 6
This means that, with SP = 3.0 bar, the system is able to ensure a con-
stant pressure to utilities that require flow rates between respectively 0 and
40 litres/minute. For higher flow rates the system works according to the
characteristic curve of the electropump at maximum rotation speed. For flow
rates lower than the limits described above, as well as ensuring constant
pressure, the system reduces the absorbed power and therefore the energy
consumption.
The above performances are to be considered measured at am-
bient temperature and water at about 20°C, during the first 10
minutes of motor operation, with water level at suction at a depth
of no more than 1 metre.
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