Outline Of Cooling Operation - Mitsubishi Heavy Industries SRK20ZMX-S Technical Manual

4 ) The difference between the outdoor air sensor temperature and the outdoor heat exchanger sensor temperature
¡ The outdoor air temperature ≧ 0ºC (model SRK50, 60 : ≧ － 2ºC) : 7ºC or higher
¡ － 15ºC ≦ The outdoor air temperature ＜ 0ºC (model SRK50, 60 : ＜ － 2ºC) : 4/15 × The outdoor air tem-
perature + 7ºC or higher
¡ The outdoor air temperature ＜ － 15ºC : － 5ºC or higher
Models SRK20～35
0
-5
-10
-15
-20
-20
5) During continuous compressor operation
In addition, when the speed command from the indoor controller of the indoor unit during heating operation has
counted 0 rps 10 times or more and all conditions of 1), 2), 3) and 5) above and the outdoor air temperature is
3ºC or less are satisfied (note that when the temperature for outdoor heat exchanger sensor (TH1) is － 5ºC or less:
62 rps or more, － 4ºC or less: less than 62 rps), defrost operation is started.
(ii) Ending conditions (Operation returns to the heating cycle when either one of the following is met.)
1) Outdoor heat exchanger sensor (TH1) temperature: 13ºC (model SRK50, 60 : 10ºC) or higher.
2) Continued operation time of defrosting → For more than 16 minutes and 50 seconds (model SRK50, 60 : 18 minutes).
Heating operation

(15) Outline of cooling operation

(a) Operation of major functional components in Cooling mode
Compressor
Indoor fan motor
Outdoor fan motor
4-way valve
Defrost operation
start
-15 -10 -5 0
Outdoor air temperature (℃)
¡Defrost operation
Max. 16 minutes and 50 seconds
(Models SRK50, 60 Max.18 minutes)
Depends on an operation condition, the time can be longer than 7 minutes.
Thermostat ON
ON
ON
ON
OFF
Models SRK50, 60
0
-5
-10
-15
-20
5 10 -20
Cooling
Thermostat OFF
OFF
ON
OFF
(few minutes ON) (few minutes ON)
OFF
53
- -
'13 • SRK-T-144
Defrost operation
start
-15 -10 -5 0
Outdoor air temperature (℃)
2~7 minutes
Hot keep operation
Failure
OFF
OFF
OFF
OFF
5 10