Oil Return Operation Of Water Heat Exchanger - Daikin VRV - WII Service Manual

Special Operation
7.2

Oil Return Operation of Water Heat Exchanger

[Oil return operation of Water heat exchanger]

When the water heat exchanger is used as evaporator during heating or simultaneous cooling/
heating operation, the operation that the oil accumulated in the water heat exchanger is returned to
compressor is conducted.
[IN condition]
After a certain continuous period of time has passed under the following conditions, oil return
operation starts.
Water heat exchanger oil return control
Parts name
Compressor
4 way valve (Main)
4 way valve
(for heat exchanger)
Main heat exchanger
electronic expansion
valve
Sub-cooling
electronic expansion
valve
Hot gas bypass
solenoid valve
Water heat exch. oil
return solenoid valve
Receiver gas
charging solenoid
Receiver gas
discharge solenoid
valve
Non-operation unit
liquid pipe stop
solenoid valve
Indoor cooling unit
fan
Indoor cooling unit
expansion valve
Indoor heating unit
fan
Indoor heating unit
expansion valve
Cooling
BS 20RH
Heating
BS 20RT
Ending condition
78
•
20S2 = 1 (Water heat exchanger is an evaporator.)
• °
& Tg – Te > 18 F
•
Elapse of a certain period of time
Electrical
Symbol
symbol
— (M1C)
20S1 (Y5S)
20S2 (Y7S)
EV1 (Y1E)
EV3 (Y3E)
SVP (Y1S)
SVE (Y2S)
SVL (Y3S)
SVG (Y4S)
SVSL (Y6S)
— (M1, 2F)
EV (Y1E)
— (M1, 2F)
EV (Y1E)
20RH (Y3S)
20RT (Y1S)
Water heat exchanger oil return control
52 Hz
ON
OFF
300 pulse
180 pulse
ON
ON
OFF
OFF
ON
Normal control
Tharmostat on : Normal control
Tharmostat off/Stop : 500 pulse
Normal control
Max.90 sec.
SiUS30-604
Function