Operation Control Function By The Outdoor Controller - Mitsubishi Heavy Industries FDT40VF Technical Manual

1.11.4 Operation control function by the outdoor controller

(Ⅰ) Models SRC40-60
(1) Defrosting operation
(a) Starting conditions (Defrosting operation can be started only when all of the following conditions are met.)
1) After start of heating operation
When it elapsed 35 minutes. (Accumulated compressor operation time)
2) After end of defrosting operation
When it elapsed 35 minutes. (Accumulated compressor operation time)
3) Outdoor heat exchanger sensor (TH1) temperature
When the temperature has been below － 5ºC for 3 minutes continuously.
4) The difference between the outdoor air sensor temperature and the outdoor heat exchanger sensor temperature
¡ The outdoor air temperature ≧ － 2ºC : 7ºC or higher
¡ － 15ºC ≦ The outdoor air temperature ＜ － 2ºC : 4/15 × The outdoor air temperature + 7ºC or higher
¡ The outdoor air temperature ＜ － 15ºC : － 5ºC or higher
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 a), b), c) and e) 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.
(b) Ending conditions (Operation returns to the heating cycle when either one of the following is met.)
1) Outdoor heat exchanger sensor (TH1) temperature: 10ºC or higher
2) Continued operation time of defrosting → For more than 18 minutes.
Heating operation
0
-5
-10
-15
-20
-20 -15 -10
Outdoor air temperature (℃)
¡Defrast operation
Depends on an operation condition, the time can be longer than 7 minutes.
-
Defrost operation
start
-5 0 5 10
Max. 18 minutes
314
-
'12 • PAC-T-173
2~7 minutes
Hot keep operation