Outline Of Cooling Operation - Mitsubishi Heavy Industries SRK20ZJX-S Service Manual

1.4 Outline of cooling operation

(1) Summary
(a) Capacity control
1) Indoor unit SRK xx ZJX-S models only
Model
Capacity
2) Indoor unit except SRK xx ZJX-S models
Model
Capacity
Capacity control is within the range shown above. If demand capacity of the indoor units exceeds the maximum capacity of
the outdoor unit, the demand capacity will be proportionally distributed.
(b) Outdoor compressor speed control
Indoor compressor command total speed value
0 rps
A rps or less
More than A rps, but B rps or less
More than B rps
Values of A, B
Model
A
B
(2) Operation of major functional components in cooling mode
Operation
Functional
components
Command speed
Fixed
Indoor
unit fan
Automatic
Outdoor unit fan
Electronic
expansion valve
Compressor
1.5 Outline of automatic operation
(1) SRK 20~60ZJX-S, SRF and SRR series
(a) Determination of operation mode
The unit checks the indoor air temperature and the outdoor air temperature after operating the indoor and outdoor blowers
for 20 seconds, determines the operation mode and the indoor air temperature setting correction value, and then enters in
the automatic operation.
Indoor air temperature (°C)
SCM40ZJ-S SCM45ZJ-S
1.8 ~ 5.9 kW 1.8 ~ 6.4 kW
SCM40ZJ-S SCM45ZJ-S
1.8 ~ 5.8 kW 1.8 ~ 6.3 kW
Decision speed
0 rps
A rps
A rps to B rps
B rps
SCM40ZJ-S SCM45ZJ-S
30 rps 30 rps
100 rps 120 rps
Thermostat OFF
Cooling
(All indoor units)
Multi-operation rpm calculated based
on the rpm required for each indoor unit (All indoor units)
According to command speed According to mode switching
According to outdoor unit speed
According to decision
According to stop mode
speed
ON
27.5
25.5
19.5
SCM50ZJ-S SCM60ZJ-S
1.8 ~ 7.1 kW 1.8 ~ 7.5 kW
SCM50ZJ-S SCM60ZJ-S
1.8 ~ 6.9 kW 1.8 ~ 7.3 kW
SCM50ZJ-S SCM60ZJ-S
30 rps 20 rps
120 rps 120 rps
Thermostat OFF
(Some of indoor units)
0 0
(Thermostat off units)
According to mode switching
OFF According to outdoor unit speed
All closed
(Thermostat off units)
OFF ON
Dehumidifying
Heating
18
Outdoor air temperature (°C)
30
- -
'10 • SCM-SM-094
SCM71ZJ-S SCM80ZJ-S
1.8 ~ 8.8 kW 1.8 ~ 9.2 kW
SCM71ZJ-S SCM80ZJ-S
1.8 ~ 8.3 kW 1.8 ~ 8.7 kW
SCM71ZJ-S SCM80ZJ-S
20 rps 20 rps
120 rps 120 rps
Fan, stop, abnormal stop
(Some of indoor units) (Outdoor unit)
0
(Fan, stop, abnormal stop units)
According to command speed
All closed
According to stop mode
(Fan, stop, abnormal stop units)
ON
Cooling
30
Failure
0
(All units)
OFF
OFF