25
Aermec cod. 14.09 4086982_03
NRL 2000-3600 60Hz
EN
15.5.1.
EXPANSION TANK CALIBRATION
The standard pressure value for precharging the
expansion tank is 1.5 bar, and the volume is 25
litres, maximum value 6 bar. The tank must be
calibrated according to the maximum difference in
height (H) of the device (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.
16.
EXPANSION TANK CALIBRATION
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.
H max (1)
= 180.44 ft / 55 m
H = 40.19 ft /
1
2.25 m
H
H = 0 ft/0 m
Pt
ar = H /
10.2 + 0.3
Pt
ar = 21.75 psi/
1
.5 bar
Pt
ar = 21.75 psi/
1
.5 bar
H min
(2)
17.
MINIMUM WATER CONTENT
NRL
2000
2250
2500
2800
3000
3300
3600
Number of compressor/circuits
n°/n°
8/4
8/4
8/4
8/4
8/4
10/4
12/4
Minimum water conten
l/kW
(1)
4
4
4
4
4
4
4
l/kW
(2)
8
8
8
8
8
8
8
ATTENTION
It is recommended to design systems with high water content (minimum recommended values shown in table), to limit:
1. The hourly number of inversions between functioning modes.
2. Decrease in water temperature during winter defrost cycles.
KEY:
(1)
minimum water content in cooling mode
(2) minimum water content in the case of applications in process or operation at low outdoor temperatures
