22
12.5 Cooling overload control (Cool)
• This control detect outdoor pipe temperature and perform the compressor frequency restriction during cooling
operation.
12.6 Time Delay Safety Control (Restart Control)
• The compressor will not restart within three minutes after compressor is stopped.
• This control is not applicable if the power supply reset.
12.7 30 seconds Force Operation
• Once the compressor starts operation, it will not stop its operation for 30 seconds in order to cycle back
compressor oil.
• However, it can be stopped using remote control or Auto OFF/ON button at indoor unit.
12.8 Total Current Control
• By referring to table below, during normal (default) operation, the running current refer to Hi values and during
Power Save Mode, the running current refer to Lo values.
• When the outdoor unit total running current (AC) exceeds X value, compressor frequency will decrease.
• If the running current does not exceed X value for 5 seconds, compressor frequency will increase.
• However, if total outdoor unit running current exceeds Y value, compressor will be stopped immediately for 3
minutes.
CU-2S18NBU-1
Operation Mode
X (A) Y (A)
Hi 14.0 17.5
Cooling/Soft Dry (A)
Lo 7.8 17.5
Hi 14.0 17.5
Cooling/Soft Dry (B)
Lo 7.8 17.5
12.9 IPM (power transistor) Protection Control
• Overheating Prevention Control
o If IPM temperature rises to 176°F, outdoor fan speed will be increased.
o When the IPM temperature rises to 203°F, compressor operation will stop immediately.
o Compressor operation restarts when temperature decreases to 194°F.
o If IPM temperature detected less than -22°F, IPM is judged as open circuit (“F96” is indicated).
• DC Peak Current Control
o When IPM DC current exceeds set value of 30.0 ± 3.0 A, the compressor will stop.
o If the DC peak current detected within 30 seconds after operation starts, compressor will restart after 1
minute.
o If the DC peak current detected 30 seconds or more after operation starts, compressor will restart after 2
minute.
o Within 30 seconds after compressor restarts, if the DC peak current is exceeded set value continuously for 7
times, all indoor and outdoor relays will be cut off (“F99” is indicated).
• Error reset can be done by power supply reset.
