Auto-Changeover Mode; Typical Air Conditioner Group Assigning Mode - Mitsubishi Electric G-50A Technical Manual

16.1.1 Auto-changeover mode

Under this mode, the difference of the set and inlet temperature of air conditioning groups (excluding the
group under fan operation or stopping) contained in a same changeover block is measured to assign points
to each group accordingly, and from this resultant total, the changeover mode (cooling/heating) is judged
for selection.
In order to determine the changeover mode with the consideration of a ratio of the number utilizing each air
conditioner, the points by temperature difference are weighted with the capacity value of the indoor unit.
Outdoor unit
When the points of each air conditioner group are multiplied with the weighting factor as below and
summed up, cooling is selected if the result stays on a positive number (over 1) while heating is selected if
it stays on a negative number (below -1).
Table 16-2 Temperature difference between set and inlet temperature and points
Temperature difference between set
and inlet temperature
Set temperature Inlet temperature
Set temperature Inlet temperature

16.1.2 Typical air conditioner group assigning mode

Judging for cooling/heating to be operated by viewing the set and inlet temperature of assigned air
conditioner groups within a changeover block for every 15 minutes, the indoor units within the changeover
block are switched over to cooling/heating for operation collectively.
Table 16-3 Temperature difference between set and inlet temperature and points
Temperature difference between set
and inlet temperature
Set temperature Inlet temperature
Set temperature Inlet temperature
This function is only applicable to the indoor units connected to M-NET outdoor unit, but not
Notice
covering the indoor units connected to K-control outdoor unit and A-control outdoor unit.
The indoor units under stopping or fan operation are out of the object for changeover.
When setting the [Typical air conditioner group assigning mode], the control will be
performed automatically with the [Auto-changeover mode] if the typical group is stopped
or under fan operation.
Since the operation mode is determined by judging the status of each indoor unit
comprehensively under the [Auto-changeover mode], comfort may not be maintained at
the surrounding of the air conditioner partially. In such case, use a proper air conditioner
as the typical group under the [Typical air conditioner group assigning mode].
104
Group 1 Group 2
4.5kW 4.5kW 4.5kW
Group 4
7.1kW 7.1kW 7.1kW
Figure 16-2 Weighting of air conditioner group
| |
0 t
0
0
0
Keeping present state
Keeping present state
Group 3
Weighting
= Group capacity/Whole capacity
4.5kW
Group 1 = 9.0/46.4
Group 2 = 4.5/46.4
Group 3 = 11.6/46.4
Group 4 = 21.3/46.4
7.1kW
Temperature difference and points
|
1.5 1.5 t
1 x weighting
-1 x weighting
Temperature difference and points
| |
t 1.5
. =
. 19 (%)
. =
. 10 (%)
. =
. 25 (%)
.
= . 46 (%)
|
3.0 3.0
2 x weighting
-2 x weighting
| |
1.5 t
Cooling operation
Heating operation
| |
t