17 Operation
Installer and user reference guide
44
RXYSCQ4~6TMV1B
VRV IV-S system air conditioner
4P404224-1C – 2019.07
17
Operation
17.1
Operation range
Use the system in the following temperature and humidity ranges for
safe and effective operation.
Cooling
Heating
Outdoor
temperature
–5~46°C DB
–20~21°C DB
–20~15.5°C WB
Indoor
temperature
21~32°C DB
14~25°C WB
15~27°C DB
Indoor humidity
≤80%
(a)
(a)
To avoid condensation and water dripping out of the unit. If
the temperature or the humidity is beyond these conditions,
safety devices may be put in action and the air conditioner
may not operate.
Above operation range is only valid in case direct expansion indoor
units are connected to the VRV IV-S system.
Special operation ranges are valid in case of using AHU. They can
be found in the installation/operation manual of the dedicated unit.
Latest information can be found in the technical engineering data.
17.2
Operating the system
17.2.1
About operating the system
▪ Operation procedure varies according to the combination of
outdoor unit and user interface.
▪ To protect the unit, turn on the main power switch 6 hours before
operation.
▪ If the main power supply is turned off during operation, operation
will restart automatically after the power turns back on again.
17.2.2
About cooling, heating, fan only, and
automatic operation
▪ Changeover cannot be made with a user interface whose display
shows
"change-over under centralised control" (refer to
installation and operation manual of the user interface).
▪ When the display
"change-over under centralised control"
flashes, refer to
"17.5.1 About setting the master user
.
▪ The fan may keep on running for about 1 minute after the heating
operation stops.
▪ The air flow rate may adjust itself depending on the room
temperature or the fan may stop immediately. This is not a
malfunction.
17.2.3
About the heating operation
It may take longer to reach the set temperature for general heating
operation than for cooling operation.
The following operation is performed in order to prevent the heating
capacity from dropping or cold air from blowing.
Defrost operation
In heating operation, freezing of the outdoor unit's air cooled coil
increases over time, restricting the energy transfer to the outdoor
unit's coil. Heating capability decreases and the system needs to go
into defrost operation to be able to remove frost from the outdoor
unit’s coil. During defrost operation the heating capacity on the
indoor unit side will temporarily drop until defrosting is completed.
After defrosting, the unit will regain its full heating capacity.
The indoor unit will stop fan operation, the refrigerant cycle will
reverse and energy from inside the building will be used to defrost
the outdoor unit coil.
The indoor unit will indicate defrost operation on the display
.
Hot start
In order to prevent cold air from blowing out of an indoor unit at the
start of heating operation, the indoor fan is automatically stopped.
The display of the user interface shows
. It may take some
time before the fan starts. This is not a malfunction.
INFORMATION
▪ The heating capacity drops when the outside
temperature falls. If this happens, use another heating
device together with the unit. (When using together with
appliances that produce open fire, ventilate the room
constantly). Do not place appliances that produce open
fire in places exposed to the air flow from the unit or
under the unit.
▪ It takes some time to heat up the room from the time
the unit is started since the unit uses a hot-air
circulating system to heat the entire room.
▪ If the hot air rises to the ceiling, leaving the area above
the floor cold, we recommend that you use the
circulator (the indoor fan for circulating air). Contact
your dealer for details.
17.2.4
To operate the system
1
Press the operation mode selector button on the user interface
several times and select the operation mode of your choice.
Cooling operation
Heating operation
Fan only operation
2
Press the ON/OFF button on the user interface.
Result:
The operation lamp lights up and the system starts
operating.
17.3
Using the dry program
17.3.1
About the dry program
▪ The function of this program is to decrease the humidity in your
room with minimal temperature decrease (minimal room cooling).
▪ The micro computer automatically determines temperature and
fan speed (cannot be set by the user interface).
▪ The system does not go into operation if the room temperature is
low (<20°C).
17.3.2
To use the dry program
To start
1
Press the operation mode selector button on the user interface
several times and select
(program dry operation).
2
Press the ON/OFF button of the user interface.
Result:
The operation lamp lights up and the system starts
operating.
3
Press the air flow direction adjust button (only for double-flow,
multi-flow, corner, ceiling-suspended and wall-mounted). Refer
to
"17.4 Adjusting the air flow direction" on page 45
To stop
4
Press the ON/OFF button on the user interface once again.
Result:
The operation lamp goes out and the system stops
operating.
