(f) 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 by
high pressure
breaker
Forcible frequency
reduction
release value
Forcible frequency
reduction
start value
Error stop
Ordinary
90
116
113
140 bar
Lower limit of forcible frequency reduction: 40 rps
(g) 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)
Forcible frequency
reduction start value
Ordinary
(h) Discharge temperature overheat prevention (Overload control)
1. 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 highstage 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.
2. 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 unit is stopped with the error stop. (Alarm code “E36” is displayed.)
User Guide | Optyma™ iCO2
© Danfoss | Climate Solutions | 2023.01 | LCA012A030
BC408445719305en-000101 | 11