Daikin REMQ5U7Y1B, Installer And User Reference Manual

Page: 27 / 176

8 | Operation
Installer and user reference guide
27
REYQ8~20+REMQ5U7Y1B
VRV IV+ heat recovery
4P561154-1A – 2020.10
8.2.2 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
"About setting the master user interface" [
4
31].
▪ 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.
8.2.3 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.
In case of Then
REYQ10~54 multi-models The indoor unit will continue heating operation at a
reduced level during defrost operation. It will
guarantee a decent comfort level indoor.
REYQ8~20 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.