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

1.3 Outline of heating operation

(1) Summary
(a) Capacity control
1) Indoor unit SRK 20~60 ZJX-S models only
Model
Capacity
2) Indoor unit except SRK 20~60 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
Item
A
B
Item
A
More than three connection
B
More than two connection
(2) Operation of major functional components in heating mode
Operation
Functional
components
Command speed
Fixed
Indoor
unit fan
Automatic
Outdoor unit fan
Electronic
expansion valve
Compressor
(3) Hot keep operation
If the hot keep operation is selected during the heating operation, the indoor fan is controlled based on the temperature of the
indoor unit heat exchanger (Th2) to prevent blowing of cool wind.
Note (1) Refer to the FDTC series by 21 page.
SCM40ZJ-S SCM45ZJ-S
1.4 ~ 6.9 kW 1.4 ~ 7.4 kW
SCM40ZJ-S SCM45ZJ-S
1.4 ~ 6.7 kW 1.4 ~ 7.2 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
Model
SCM60ZJ-S
Two connection
One connection
Thermostat OFF
Heating
(All indoor units)
Multi-operation rpm calculated based
on the rpm required for each indoor unit (All indoor units)
According to mode switching
According to command speed
According to outdoor unit speed
According to decision
According to stop mode
speed
ON
SCM50ZJ-S SCM60ZJ-S
1.4 ~ 7.5 kW 1.5 ~ 7.8 kW
SCM50ZJ-S SCM60ZJ-S
1.4 ~ 7.3 kW 1.5 ~ 7.6 kW
SCM50ZJ-S
30 rps
120 rps
SCM71ZJ-S SCM80ZJ-S
40 rps
30 rps
90 rps
120 rps
Thermostat OFF
(Some of indoor units)
0 0
(Thermostat off units)
According to mode switching
Hot Keep
Hot Keep According to command speed
OFF According to outdoor unit speed
According to heating stop unit control
(Thermostat off units)
OFF ON
28
- -
'10 • SCM-SM-094
SCM71ZJ-S SCM80ZJ-S
1.5 ~ 9.4 kW 1.5 ~ 9.8 kW
SCM71ZJ-S SCM80ZJ-S
1.5 ~ 9.1 kW 1.5 ~ 9.5 kW
Fan, stop, abnormal stop Failure
(Some of indoor units) (Outdoor unit)
0
(Fan, stop, abnormal stop units) (All units)
Hot Keep
Hot Keep
According to heating stop unit control
According to stop mode
(Fan, stop, abnormal stop units)
ON
0
OFF
OFF