Refrigeration Cycle System Protective Control - Mitsubishi Heavy Industries SCM50ZS-W Service Manual

(7) Refrigeration cycle system protective control

(a) Starting condition
This control starts when the following conditions are satisfied.
(i) When it has elapsed 30 minutes after the compressor was changed from OFF to ON in the cooling operation mode
for more than 5 minutes.
(ii) When the compressor command speed has satisfied the following conditions.
(iii) When the indoor air temperature of running indoor unit (Th1 (Thi-A)) and the indoor heat exchanger temperature (Th2
(Thi-R1)) have satisfied the following condition even on one unit.
(iv) Except following mode
• Silent mode
Compressor
Unit
command speed
40 rps
1
2 50 rps
60 rps
3
(b) Contents of control
(i) Stop the compressor and delay the start, and then restarts.
(ii) Compressor stops by the abnormal stop when the compressor stop has occurred 3 times in one hour.
(8) Service valve (gas side) closing operation
(a) Starting conditions
(i) Operation mode : Heating
(ii) Compressor conditions : OFF → ON
(b) Contents control
If the output current of inverter exceeds the specifications, it makes the compressor stopping.
(c) Anomalous stop control
If the inverter output current value excceds the setting value within 80 seconds the compressor stops.
Indoor air temperature Indoor air temperature (Th1) and indoor
(Th1 ℃ )
heat exchanger temperature (Th2)
10 < = Th1 < = 40
70
-
Th1 - 4 < Th2
Th1 - 3 < Th2
-
'19 • SCM-SM-281
Duration
5 minute