Mini UM S/M
Special Control
Function
39
3.2.2 Oil Return Operation in Heating Operation
[Conditions to start]
The heating oil-returning operation is started referring following conditions.
Integrated amount of displaced oil
Timer
(After the power is turned on, integrated operating-time is 2 hours and subsequently every 8
hours.)
In addition, integrated amount of displaced oil is derived from Tc, Te, and the compressor
load.
* From the preparing oil-returning operation to the oil-returning operation, and from the oil-
returning operation to the operation after oil-returning, the compressor stops for 1 minute to
reduce noise on changing of the four way valve.
Outdoor Unit Actuator
Oil return preparation
operation
Oil return operation
Post-oil-return operation
Compressor
Upper limit control
124 Hz
2-step increase from
52 Hz to
(Pc - Pe>0.4 MPa) time
Outdoor unit fan
STEP8
OFF
STEP8
Four way valve
ON
OFF
ON
Main electronic expansion valve
(EV1)
SH control
1400 pls
200~400 pls
Subcooling electronic expansion
valve (EV2)
0 pls
0 pls
0 pls
Hot gas bypass valve (SVP)
OFF
ON
ON
Receiver gas discharging valve
(SVG)
ON
ON
OFF
Ending conditions
130 sec.
•
6 min.
•
Ts - Te<5
•
160 sec.
•
Pc - Pe>0.4MPa
or
or
Indoor unit actuator
Heating oil return operation
Fan
Thermostat ON unit
OFF
Stopping unit
OFF
Thermostat OFF unit
OFF
Electronic expansion valve
Thermostat ON unit
500 pls
Stopping unit
500 pls
Thermostat OFF unit
500 pls
Mini UM.book Page 39 Monday, January 24, 2005 11:32 AM
