Refrigerant Circuit Safety Valves; Heat Exchanger Pressure Drop; Control And Safety Calibrations - Trane CXAO Installation Operation & Maintenance

2.17

Refrigerant circuit safety valves

Each system comes with safety valves that are installed
on each circuit, both on the evaporator and on the
condenser.
The purpose of the valves is to discharge the refrigerant
inside the refrigerating circuit in the event of any
malfunction.
WARNING! This unit is designed for installation
outdoors. However, check that there is suffi cient air
circulation around the unit. If the unit is installed in
closed or partly covered areas, possible damage from
inhalation of refrigerant gases must be avoided. Avoid
releasing the refrigerant in the environment. The safety
valves must be connected externally. The installer is
responsible for connecting the safety valves to the
discharge piping and for establishing their size.
SCREW
SCROLL
ANTIFREEZE
Ethylene glycol correction factors
% Ethylene glycol
weight
Freezing
temperature
Suggested
security limit
Cooling capacity
coeffi cient
Power input
coeffi cient
Flow rate
coeffi cient
Pressure drop
coeffi cient
Glycol percentage depending on freezing temperature
Freezing
temperature
% Ethylene glycol
Flow rate coeffi cient
In order to calculate performance with glycoled solutions, multiply the main sizes by the respective coeffi cients.
RF-SVX003A-GB
RELIEF VALVE
24,5 BAR
45 BAR
4°C
5% 10%
°C -2% -3,9
°C 3 1
- 0,995 0,99
- 0,997 0,993
- 1,003 1,01
- 1,029 1,06
0°C -5°C
5% 12%
1,02 1,033
Refrigerant circuit safety valves
2.18

Heat exchanger pressure drop

It is possible to use units with different fl ow rates from
the nominal ones and consequently with different
temperature differences from nominal. It is not
recommended to operate with thermal jumps too high,
since very low water fl ow may cause coil freezing with
automatic exclusion of warranty, or vice versa, too low,
since very high water fl ow rates result in excessive water
velocity and possible erosion / corrosion. In the fi rst
case low speed can lead to underperformance and easy
scaling, and in the second case must install pumps with
high prevalence energetically little valid.
2.19

Control and safety calibrations

SCALING CORRECTION SCHEDULES
The following table provides information on the organs
of action and safety of the unit. Always verify that the
unit is within the limits imposed by pressure switches
or pressure transducers and periodically check the
calibration.
HIGH PRESSURE SWITCH
17 BAR
41 BAR
4°C
15% 20% 25%
-6,5 -8,9 -11,8
-1 -4 -6
0,985 0,981 0,977
0,99 0,988 0,986
1,02 1,033 1,05
1,09 1,118 1,149
-10°C -15°C
20% 28%
1,05 1,072
30% 35% 40%
-15,6 -19 -23,4
-10 -14 -19
0,974 0,971 0,968
0,984 0,982 0,981
1,072 1,095 1,124
1,182 1,211 1,243
-20°C -25°C
35% 40%
1,095 1,124
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