22
The pressures shown here are net
of the pressure drops of the heat
exchangers, filter, etc.
They should therefore be considered
useful for the system
WARNING
As in the configurator, the pumps can
be high or low pressure, so we will
give two distinct diagrams to avoid
confusion in the selection.
11.1 LOW PRESSURE
PUMPS
must be installed, measured (using the
common criteria) with reference to the
additional volume of water.
From the following tables, it is possible
to obtain the values of maximum
system content, also for other
operational conditions with glycol
water.
The values are obtained by multiplying
the reference value by the correction
coefficient.
10.1.1 Calibration of expansion tank
The standard value of pre-charge
pressure of the two expansion tanks is
1.5 bar, while their volume is 24 litres,
maximum value 6 bar.
The calibration of the tanks must be
regulated on the basis of the maximum
difference of level (H) of the user (see
figure), according to the formula:
p (calibration) [bar] = H [m] / 10.2
+ 0.3.
For example, if the level difference H is
20m, the calibration value of the tank
will be 2.3 bar.
If the calibration value obtained from
the calculation is lower than 1.5 bar
(i.e. for H < 12.25), maintain the
standard calibration.
H max
(1)
= 55 m
H = 12.25 m
H
H = 0 m
Ptar = H / 10.2 + 0.3
Ptar = 1.5 barPtar = 1.5 bar
H min
(2)
KEY
(1)
Check that the highest user does
not exceed a level difference of 55
metres.
(2) Check that the lowest user can
sustain the global pressure acting
at that point.
11 EFFECTIVE PRESSURE FOR THE SYSTEM
Water flow rate m3/h
kPa
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