Daikin VRV III REYQ8PY1 Service Manual page 103

Refrigerant Flow for Each Operation Mode
Pressure equalizing when switching operation cooling/ heating
1. When switching operation from to cooling to heating
In cooling
operation
In equalization
To heating
operation
92
First, the electric expansion valves for EVHS, EVH, EVL and EVLS of the indoor unit will be
closed.
Next, open the EVHS, and it makes to balance the system pressure.
Finally, EVH and EVHS are opened and the electric expansion valve of the indoor unit is
opened to start the operation as a heating circuit.
Indoor Unit
Cooling
Unit
Indoor Unit
(Close)
Indoor Unit
Heating
Unit
BS Unit
Liquid
Pipe
EVSC
EVHS
Dual
Pressure
Gas Pipe
EVH
EVL
Suction
Pipe
EVLS
BS Unit
Liquid
Pipe
EVSC
EVHS (Open)
Dual
Pressure
Gas Pipe
EVH (Close)
EVL (Close)
Suction
Pipe
EVLS (Close)
BS Unit
Liquid
Pipe
EVSC
EVHS
Dual
Pressure
Gas Pipe
EVH
EVL
Suction
Pipe
EVLS
Si37-701
Refrigerant Circuit