DAB Esybox Serie Instructions Pour L'installation Et L'entretien page 43

However, these parameters and others can be set according to the system.
All the settable values are illustrated in the par. 7-8-9 pressure, intervention of protections, rotation speed, etc.
There are many other operating modes and accessory functions. Thanks to the different possible settings and the availability of configurable input
and output channels, it is possible to adapt the inverter operation to the requirements of various systems. See par. 7-8-9
3.2 Integrated Expansion Vessel
The system is complete with an integrated expansion vessel with a total capacity of 2 litres. The main functions of the expansion vessel are:
– to make the system elastic so as to protect it against water hammer;
– to ensure a water reserve which, in the case of small leaks, maintains the pressure in the system for a longer time and spreads out needless
restarts of the system which otherwise would be continuous;
– when the utility is turned on, ensure the water pressure for the seconds that the system takes to switch on and reach the correct rotation speed.
It is not a function of the integrated expansion vessel to ensure a water reserve such as to reduce interventions of the system (requests from the
utility, not from a leak in the system). It is possible to add an expansion vessel with the capacity you prefer to the system, connecting it to a point
on the delivery system (not a suction point). In the case of horizontal installation it is possible to connect to the unused delivery outlet. When
choosing the tank, consider that the quantity of water released will also depend on the parameters SP and RP that can be set on the system (par.
8-9).
The expansion vessel is preloaded with pressurised air through the valve accessible from the technical compartmen (Fig.3, point.1). The preload
value with which the expansion vessel is supplied by the manufacturer 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 2 litres, any operation to check the air pressure must be performed by connecting
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: disconnect 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 quantity 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.
3.3 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 possibility of locating it even in recesses without ventilation.
The diagram in Fig Fig.6 shows the curves 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 with set point
at 3.0 bar.
Where:
Pair = air pressure value in bar
SP = Set Point (9.3) in bar
RP = Reduction of pressure to restart (9.5) in bar
Pair = 3 – 0.3 – 0.7 = 2.0 bar
ENGLISH
41
Figure 6