Daikin REYQ-TA Series Service Manual page 98

Special Control
[While in cooling/heating mixed mode, single-room heating → cooling]
First, the electronic expansion valve of the indoor unit in heating operation will close, and the Y2E and Y3E electronic
expansion valves of the branch selector unit will all close once.
Next, the Y3E electronic expansion valve will open little by little to perform pressure equalization.
Then the electronic expansion valve will fully open, and the electronic expansion valve of the indoor unit will open to
activate the heating circuit.
The required switching time is approximately 6 minutes. (Field settings, however, can shorten the time from 6 minutes to 4
minutes.)
(1) In heating
(2) In equalization
(3) To cooling
85
Indoor unit
Heating unit
Indoor unit
(close)
In equalization
Indoor unit
Cooling unit
Branch selector unit
Liquid pipe
Y1E
Dual pressure gas pipe
Y2E
Y3E
Suction gas pipe
Branch selector unit
Liquid pipe
Y1E
Dual pressure gas pipe
Y2E (open)
Y3E (close)
Suction gas pipe
Branch selector unit
Liquid pipe
Y1E
Dual pressure gas pipe
Y2E
Y3E
Suction gas pipe
SiUS371614E
Functions and Control