Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 1045

(iii) Three minutes delay timer
The compressor (inverter) will remain in stop state for 3 minutes, when the compressor is stopped by thermostat, ON/OFF
swich, and /or by occurrence of trouble. When the power source is turned ON, the 3-minutes delay timer is cancelled.
(f) Detection Control of Electricity Supply to Crank Case Heater
When an operation starts less than 6 hours after the power is turned on (electricity is supplied to CH), the frequency is
controlled as follows:
(Hz)
70
60
50
40
30
20
10
0 5 10 15
(g) Open-phase Protection
When the T-phase voltage of the secondary side of 52C is 0V, an abnormal stop will occur and the inspection displays
(Remote controller : E34, indoor unit green LED : Continuous flashing, red LED : OFF, outdoor unit green LED : red LED
: 2 times flash) will appear.
(h) Current Safe Control
The operation corrent is automatically controlled.
When the operation current at the converter inlet increases, the frequency is lowered 5 Hz by 5 Hz so that the operation
current does not increase above the set point.
Lower limit frequency: Hot gas bypass 35 Hz
1) Retain the operations with hot gas bypass of 35 Hz for 3 minutes, and when it is foud to be the current safe value, stop the
inverter, operate them with hot gas bypass 3minutes later for 3 minutes. When the frequency is below the current safe
value, operate them with full loads of 35 Hz, cancel the frequency control to bring them back to the normal operation.
2) When the decision frequency under the fuzzy control get lower than the current safe frequency during a current safe
control, bring them back to the normal operation. When the current value comes to the current cancel value during a
current safe control, retain the frequency for 3 minutes, then cancel the frequency control.
(i) Current Cut Control
This control aims to prevent over current in the converter. When the current increases above the set point, stop the inverter
immediately, then let is reset by itself 3 minutes later. After the self-reset, start the inverter with 35 Hz, and increase the
frequency 5 Hz every 3 minutes to let it return to the fuzzy indication frequency. When the current is cut four times in 15
minutes, turn off 52C bring it to an abnomal stop and the inspection displays (Remote controller : E42, indoor unit green LED
: Continuous flashing, red LED : OFF, outdoor green LED : Continuous flashing,and red LED : 1 time flash will appear.
(j) Protection of Power Transistor from Overheat
When the temperature of the power transistor increases to the set temperature, stop the inverter immediately and let is reset
by itself 3 minutes later. If the power transistor is overheated again within 2 hours, turn off 52C, bring it to an abnormal
stop and the inspection displays (Remote controller : E41, indoor unit green LED : Continuous flashing, red LED : OFF,
outdoor unit green LED : Continuous flashing, red LED : 4 times flash) will appear.
(to the decision frequency)
Notes
5Hz/minutes
33 (minutes)
20 25 30
(1) When the operation stops within 33 minutes, this
control is executed at the time of the second or later
startup.
(2) Operate with hot gas bypass up to 35 Hz, then with 60
Hz for 15 seconds.
FDC-HKXR
1043