12 Operation
Installation and operation manual
31
RWEYQ8~RWEYQ8~14T9Y1B
VRV IV water-cooled system air conditioner
4P452190-1A – 2017.04
12
Operation
12.1
Operation range
Use the system in the following temperature and humidity ranges for
safe and effective operation.
Above operation range is only valid in case direct expansion indoor
units are connected to the VRV IV system.
Special operation ranges are valid in case of using Hydrobox units or
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
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.
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
interface" on page 32
.
▪ 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 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 deliver enough heat to the indoor
units.
In case of
Then
RWEYQ16~42 multi-
models
The indoor unit will continue heating
operation at a reduced level during defrost
operation. It will guarantee a decent comfort
level indoor.
RWEYQ8~14 single
models
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.
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
1
1
Heating operation
1
1
Fan only operation
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.
