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8 - FREE-COOLING OPTION (OPTION 118A)
8.1 - Physical data, 30XA units with free-cooling option (option 118A)
30XA with Option 118A
Operating weight with option 279 or 257 kg
Refrigerant charge
Circuit A
Circuit B
Refrigerant charge, option 254
Circuit A
Circuit B
*
Option 118A (free cooling) is not compatible with these unit sizes.
8.2 - Operating limits
Cooling mode
Evaporator
Entering water temperature at start-up
Entering water temperature during operation
Leaving water temperature during operation
Condenser (air)
Outdoor ambient operating temperature
With winter operation option (option 28)
Free-cooling mode
Evaporator
Entering water temperature at start-up
Leaving water temperature during operation
Condenser (air)
Outdoor ambient operating temperature
With winter operation option (option 28)
*
Maximum configurable set-point
8.3 - Operation
7
5
8
4
9
6
3
2
Legend
1
Evaporator
2
Air condenser (coils)
3
Motorised two-way valve, discharge side
4
Compressor and oil separator
5
Principal electronic expansion valve (EXV)
6
Pressure and temperature measurement to calculate the sub-cooling upstream
of the pump
7
Motorised two-way bypass valve
8
Free-cooling expansion device (EXV)
9
Refrigerant pump
36
252
302
352
3740
3780
3820
kg
37
35
35
38.5
37.5
37.5
kg
60
64
*
64
64
*
Minimum Maximum
°C
-
45
°C
6.8
21
3.3
15
°C
-10
55*
°C
-20
55*
Minimum Maximum
°C
-
45
3.3
26*
Minimum Maximum
°C
-10
20
°C
-20
20
1
7
5
8
9
6
2
402
452
502
602
4673
4743
5174
6097
51.5
53.5
60.5
60
36.5
37
36
61
87
87
104
104
56
56
56
90
The change-over between the cooling and free-cooling
modes is automatically controlled (it is possible to block the
change-over to free-cooling by reconfiguring the machine
- see Controls IOM). The configurable parameters
permitting change-over are the outside air temperature and
the leaving water temperature set-point. As soon as the
temperature difference LWT
current capacity in cooling mode is calculated and
compared with the theo-retical free-cooling capacity. This
comparison authorizes/stops the change-over to free-
cooling.
After change-over to free-cooling all compressors are
stopped, the two (or four) two-way valves change to the
free-cooling position (the compressor functions are
bypassed). As soon as the valves open, the free-cooling
pump is started. This change-over logic takes around 4
minutes. Taking this timing into consideration two cooling
- free-cooling change-overs are authorized per hour.
If the capacity supplied in the free-cooling mode is insuffi-
cient (set-point not reached), the unit automatically changes
over to cooling mode.
To optimize operation in free-cooling mode we strongly
recommend to use the set-point offset function. This favours
the change-over to free-cooling and increases the capacity
4
in free-cooling mode.
3
702
752
802
852
6247
6547
6847
7308
60
67
71
74
64
60
67
65
102
*
*
133
97
*
*
97
- OAT is above 8 K the
stp
902
1002
7648
8226
71
78
78
82
*
143
*
132
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