CO
2
NNEXT
rev.01
EN
70 / 293
Refrigerant pressure defect
The causes that can cause lowering of the intake pressure beyond the values permitted in the project are:
x
defect in the quality of refrigerant loaded;
x
poor regulation of the thermostatic valves;
x
gas leaks that reduce the load.
This entails a drastic reduction in the thermodynamic efficiency of the system and can cause compressor
failure. If the reduction occurs at values lower than the calibration one, the protection from electronic control
of minimum pressure comes into operation. This intervention blocks the compressor motor and reset is
automatic. If the intake side pressure increases again, the system automatically restarts. This can of course be
accepted if it were a transitory phenomenon while it requires maintenance if the phenomenon continues to
be repeated.
Electronic control malfunction
In the event of malfunction of the electronic control acting on the compressors, electronic valves and on the
gas-cooler, there may be limited functionality or system shutdown depending on the type of fault. The high
pressure safety related to the pressure switches, independent of the electronic control, continues to be
active. Probe reading failure or breakage of the probes, related to electronic control, may limit certain
features or generate system shutdown. All malfunctions can be acquired by a supervisory system. Malfunction
of the electronic control does not generate a risk for personal safety.
Insufficient lubrication of the compressor
In the oil circuit (if any) there is an oil separator, positioned on the general supply route, which redistributes the
oil collected to the compressors themselves through appropriate logics and circuits.
Furthermore, the electronic control includes checking of the compressor speed in order to guarantee the
correct oil return to the compressor.
