Protective Control Function - Mitsubishi SRK18CL Technical Manual & Parts List

(9) Protective control function

(a) Frost prevention for indoor heat exchanger (During cooling or dehumidifying)
1) Operating conditions
a) Indoor heat exchanger temperature is lower than 2.5ºC.
b) 3 minutes elapsed after the start of operation.
2) Detail of frost prevention operation
Compressor
Indoor fan
Outdoor fan
3) Reset condition: Indoor heat exchanger temperature is higher than 15ºC.
(b) Indoor fan motor protection
When the airconditioner is operating and the indoor fan motor is turned ON, if the indoor fan motor has operated at 300 rpm or
under for more than 30 seconds, the unit enters first in the stop mode and then stops the entire system.
TIMER light illuminates simultaneously and the RUN light flashing 6 times at each 8-second.
(c) 3 minutes forced operation
When the compressor begins operating the thermal operation is not effective for 3 minutes, so operation continues as is in the
operation mode. (After 3 minutes has passed the thermal operation is effective.)
However, stopping the compressor via a stop signal or protection control has priority.
(d) Abnormality of outdoor unit
When the indoor heat exchanger temperature does not fall to 25ºC or below for 40 minutes after 5 minutes have elapsed since the
compressor operation start, the abnormality stop occurs. (The TIMER light flashes 2 times.)
(e) Sensor disconnection (room temperature, indoor heat exchanger)
1) Room temperature sensor
If the temperature detected by the room temperature sensor is – 45ºC or lower continuously for 15 seconds or longer while
operation is stopped, an error indication is displayed. (RUN light: 2 time flash, TIMER light: ON)
2) Indoor heat exchanger temperature sensor
If the temperature detected by the indoor heat exchanger temperature sensor is –28ºC or lower continuously for 15 seconds
or longer while operation is stopped, an error indication is displayed.
(RUN light : 1 time flash, TIMER light : ON)
OFF
Protects the fan tap just before frost prevention control.
Depending on the stop mode

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'12 • SRK-T-125