Heat Exchanger Control - Daikin RXYQ96PYDN Service Manual

SiUS34-801A_b
circulation rate to be supplied to indoor units.
6.6

Heat Exchanger Control

While in heating or cool/heat simultaneous operation, ensure target condensing and evaporating
temperature by changing over the air heat exchange of outdoor unit to the evaporator or the
condenser in response to loads.
[Single system]
VRVIII R-410A Heat Recovery 60Hz
Pc>475.6psi
Pc>461.1psi
Pc>446.6psi
Lapse of 20 sec.
-1 step on
outdoor unit fan
PI control
Outdoor unit
Left side Right side
Condenser Condenser
GR > 25 GR < -20
Outdoor unit
GR > 25
Left side Right side
GR < -20
Evaporator Condenser
Fan step 9
PI control
Fan step 8
PI control
Fan step 7
PI control
PI control
Hold the current
step on outdoor
unit fan
Lapse of 20 sec.
Outdoor unit
Left side Right side
Evaporator –
GR > 15 GR < -10
Outdoor unit
Left side Right side
Evaporator Evaporator
Basic Control
+1 step on
outdoor unit fan
Note 1. "GR" is a numeric value
representing the current
balanced condition and
calculated from target
condensing temperature,
target evaporating
temperature, current
condensing temperature,
and current evaporating
temperature.
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