Daikin VRV II RXYQ5MY1B Service Manual page 122

SiE39-404
(2) Heating operations
Discharge
air
T4
EV
T1: Temperature detected by suction air thermistor Th1
T2: Temperature detected by liquid pipe temp. thermistor Th2
T3: Temperature detected by gas pipe temp. thermistor Th3
T4: Temperature detected by discharge air thermistor Th4
Tc : Outdoor unit condensing temperature
EV: Electronic expansion valve opening
If the discharge temperature
T4 is lower than the discharge
setting temperature Ts
No
Is EV possible
Judge if the superheat degree
is not too small when the EV is
opened.
EV=EV+∆EV
Function
T2
SC=Tc–T2
Yes
T4 < Ts?
to open?
Yes
If yes,
EV is opened
CPU
T1
Calculate superheat degree.
No
EV possible to
close?
Yes
If yes,
EV is closed.
EV=EV–∆EV
Outline of Control (Indoor Unit)
Refrigerant
Tc
(From Outdoor unit)
Ts
Temp.
Setting
Refrigerant
If the discharge temperature T4
is higher than the discharge
setting temperature Ts
Is
No
Judge if the superheat degree
is not too large when the EV is
closed.
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