5-6
FIELD WORK INSTRUCTION
5.6
Attention for SET-FREE FXG/FX3 Series
The SET-FREE FXG/FX3 series has been designed for the system to provide simultaneous cooling and
heating operations during intermediate seasons and the refrigerant cycle is controlled according to heat
balance of cooling and heating. Therefore, pay attention to the followings for the selection of installing sites
and the installation work.
As especially, this SET-FREE FXG series is operated by mixed refrigerant R407C (FXG), special attention is
required. Follow the items below.
* The SET-FREE FXG/FX3 series is for general office building air conditioning. Therefore, it is
recommended that different air conditioning systems be selected in a place where systems are utilized for
(i) machine rooms or computer rooms, providing big heat load and (ii) thermostatic chamber, requiring
precise temperature control.
* By operating this unit with other cooling/heating equipment at the same time, thermo-ON/OFF may occur
frequently or the heat load change may be big, and it may cause the decrease of the unit performance or
shorten the lifetime of the unit. Do not install the unit in a place where operation with other cooling/heating
equipment is required.
<Attention for System Design of FXG/FX3 Series>
(1) Installing Site:
Do not install the unit in such places;
(a) where temperature difference among rooms is excessively big and the heat load when cooling and
heating is excessively big during simultaneous COOL/HEAT operation.
(b) where the heat load change of a room is big and thermo-ON/OFF may occur frequently especially
during simultaneous COOL/HEAT operation.
(c) where temporary capacity decrease according to ON/OFF operation of other rooms is not allowed.
(d) where starting up in simultaneous COOL/HEAT operation mode is always required.
(2) Piping Work:
Do not perform the piping work as follows;
(a) The piping length between the farthest indoor unit and the last multi-kit is excessively long.
(b) The CH units are used individually for each indoor unit in a same room.
(c) There is a height difference between CH units.
Refer to the followings for the attention in detail. (Observe the attentions common to FSG/FS3 series.)
<Attention for Simultaneous COOL/HEAT Operation>
(1) Capacity of Simultaneous COOL/HEAT Operation:
[Phenomenon]
During the simultaneous cooling and heating operation, the capacity comparatively decreases when
compared with the capacity whilst operating all the indoor units at the same mode.
The capacity decrease mentioned above should be taken into consideration when in actual operation,
especially for the small capacity units (0.8 to 1.5HP).
100
80
50
0
0
(5)
21
Outdoor Air Temperature (˚C DB)
Mainly Heating
Operation
All Indoor Units in
Cooling Operation /
Mainly Cooling Operation
Cooling Capacity (%)
100
80
50
0
0
(5)
21
Outdoor Air Temperature (˚C DB)
Mainly Heating
Operation
All Indoor Units in
Heating Operation /
Mainly Heating Operation
Heating Capacity (%)
<Cooling>
<Heating>
