Instructions
32 | AN405821998738en-000102 - 118A5495A
© Danfoss | Climate Solutions | 2023.02 | LCA012A024
6. High pressure overshoot prevention (Overload control)
This control suppresses the high pressure (HP) from rising excessively.
If the detected high pressure (HP) exceeds a preset value, the frequency output is controlled.
Restriction on the frequency output
Forcible frequency decrease … Start value: 116 bar, release value: 113 bar
Stop by pressure overshoot
High pressure breaker ……………… Setting value: 140 bar
(Displays the alarm code “E40”.)
Error stop
Ordinary
90
116
113
140 (Bar)
Forcible frequency
reduction release
value
Forcible frequency
reduction start
value
Error stop by high
pressure breaker
Lower limit of forcible frequency reduction: 40 rps
7. Over-current prevention (Overload control)
This control suppresses the compressor operating current from rising excessively. If the detected secondary current of inverter becomes higher than the
value preset as shown below, the frequency output is restricted by the control PCB of condensing unit.
Restriction of frequency output
Forcible frequency reduction … Start value: 23 A, release value: 22 A
22 (A)
After 3 minutes
23 (A)
Ordinary
Forcible frequency
reduction start value
8. Discharge temperature overheat prevention (Overload control)
When the temperature of gas discharged (Td) from each compressor becomes too higher, the aperture of liquid bypass electronic expansion valve is
controlled in order to cool the state of high-stage suction gas and lower the high-stage discharge gas temperature by bypassing 2-phase flow (liquid/gas)
at the gas cooler outlet to the compressor medium pressure injection. If the discharge temperature exceeds 135 °C, the compressor frequency decreases.
• When the discharge gas temperature (Td) rises to 150°C even if this control is turned on, the condensing unit is stopped with the retry stop.
If the retry stop repeats 5 times, however, the machine is stopped with the error stop.
(Alarm code “E36” is displayed.)
Fig. 29
Fig. 28