DAB E.sybox Instrucciones Para La Instalación Y El Mantenimiento página 68

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ENGLISH
• 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.6-7).
The expansion vessel is preloaded with pressurised air through the valve
accessible from the technical compartment (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 – 0.7bar
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).
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Where:
- Pair = air pressure value in bar
- SP = Set Point (par.7.3) in bar
- RP = Reduction of pressure to restart
(par. 7.5.1) in bar
Pair = 3.0 – 0.3 – 0.7 = 2.0 bar
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 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:
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 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.
1.3 Integrated electropump
The system has a built-in multi-impeller centrifugal electropump. Specifi-
cally, the electropump comprises a hydraulic assembly of 5 impellers
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 pos-
sibility of locating it even in recesses without ventilation.
The graph in Fig.6 shows in red the characteristic curve of the hydraulic
performance of the electropump at maximum rotation speed (pump not
controlled by the inverter). This gives:
maximum flow rate = 120 l/min;;
•
maximum head = 65 m => about 6.5 bar maximum pressure.
•