12 Operation
Installation and operation manual
26
RKXYQ5T7Y1B
VRV IV compressor unit for indoor installation
4P408443-1 – 2015.07
Specification
RDXYQ5
Outside ambient
design temperature
Heating
–20~15.5°C WB
Cooling
–5~46°C DB
Ambient design temperature of compressor
unit and heat exchanger unit
5~35°C DB
(26°C WB)
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.
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.
12.2
Operating the system
12.2.1
About operating the system
▪ Operation procedure varies according to the combination of
compressor unit, heat exchanger 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.
▪ When stopping the unit, the unit might still operate for a few
minutes. This is not a malfunction.
12.2.2
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
"12.5.1 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.
12.2.3
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 heat exchanger unit's air cooled
coil increases over time, restricting the energy transfer to the heat
exchanger unit's coil. Heating capability decreases and the system
needs to go into defrost operation to be able to deliver enough heat
to the indoor units:
The indoor unit will stop fan operation, the refrigerant cycle will
reverse and energy from inside the building will be used to defrost
the heat exchanger unit coil.
The indoor unit will indicate defrost operation on the displays
.
During defrost operation, ice melts and possibly evaporates.
Possible consequence:
Mist might be visible during or directly after
defrost operation. This is not a malfunction.
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.
12.2.4
To operate the system (WITHOUT cool/
heat changeover remote control switch)
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.
12.2.5
To operate the system (WITH cool/heat
changeover remote control switch)
Overview of the changeover remote control switch
a
b
a
FAN ONLY/AIR CONDITIONING
SELECTOR SWITCH
Set the switch to
for fan only
operation or to
for heating or
cooling operation.
b
COOL/HEAT CHANGEOVER SWITCH
Set the switch to
for cooling or to
for heating
To start
1
Select operation mode with the cool/heat changeover switch as
follows:
Cooling operation
Heating operation
Fan only operation
1
1
1
1
1
2
Press the ON/OFF button on the user interface.
Result:
The operation lamp lights up and the system starts
operating.
To stop
3
Press the ON/OFF button on the user interface once again.
Result:
The operation lamp goes out and the system stops
operating.
NOTICE
Do not turn off power immediately after the unit stops, but
wait for at least 5 minutes.
