General Operation - Daikin VRV IV+ Service Manual

https://daikin-p.ru/catalog/vrv-daikn/naruzhnye-vrv-bloki-daikin

1 General operation

1 General operation
The VRV IV+ hp outdoor unit is a heat pump used for cooling or
heating in commercial applications.
Outdoor units
The outdoor unit consists of:
▪ 1 or 2 inverter compressor(s)
▪ A switchbox containing necessary PCBs
▪ A liquid cooling circuit to cool down inverter switchbox
▪ An air cooled heat-exchanger
▪ 3 expansion valves (main, sub-cool and liquid cooling)
▪ 1 or 2 fan motor(s)
▪ Two refrigerant piping connections: gas and liquid.
There are 3 types of outdoor units:
▪ RXYQ-U: VRV IV+ hp, non-continuous Heating
▪ RYYQ-U: VRV IV+ hp, continuous Heating
▪ RYMQ-U: VRV IV+ hp, continuous Heating
RYYQ-U units can ONLY be used as stand-alone units and not in
multi combinations.
RYMQ-U units can ONLY be used in multi combinations and not as
stand-alone units.
Non-continuous heating and continuous heating type units CANNOT
be used together in multi combination.
VRV IV+ hp U-series and T-series cannot be used together in multi
combination.
Up to 3 modules of VRV IV+ hp outdoor units can be connected
using refnet BHFQ22P.
Field piping must be thermally insulated copper piping.
To split the refrigerant circuit between outdoor units and indoor units
(expansion valve kit in case air handling unit and BP branch selector
box in case Split or Sky air units), KHRQ22M refnet branches are
used.
The VRV IV+ hp comes in two different types of outdoor unit casing:
Small casing (8/10/12 HP) Large casing (14/16/18/20 HP)
Heating mode
The compressor capacity step is defined by the condensing
temperature, which is calculated through the high pressure sensor
read-out.
In normal operation, the outdoor unit fan is set to "fan step 7" for
nominal fan speed.
In defrost or oil return operation the heat exchanger functions as a
condenser, while its fan motor(s) and the fan motors of the
operational VRV indoor units are stopped.
Cooling mode
The compressor capacity step is defined by the evaporation
temperature, which is calculated through the low pressure sensor
read-out.
In normal operation the fan step is defined by the condensing
temperature, which is calculated through the high pressure sensor
read-out and ambient temperature thermistor read-out.
RYYQ+RYMQ+RXYQ8~20U7Y1B Service manual
VRV IV+ Heat Pump
7
ESIE18-14 – 2019.07