Special Control
SiBE18-821_C
84
Function
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 preparation to the oil return operation, and from the oil return operation to the post-
oil-return operation, 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
140 Hz Full load
2-step increase from
36 Hz Unload to (Pc –
Pe > 0.4 MPa) every
20 sec.
Outdoor fan
STEP 8
OFF
STEP 8
Four way valve (Y1S)
ON
OFF
ON
Main electronic expansion valve
(Y1E)
SH control
480 pls
55 pls
Subcooling electronic expansion
valve (Y3E)
0 pls
0 pls
0 pls
Hot gas bypass valve (Y2S)
OFF
OFF
OFF
Ending conditions
2 min.
•
12 min.
•
Ts1 – Te < 5°C
•
Tb > 11°C
•
160 sec.
•
Pc – Pe > 0.4 MPa
or
&
{
or
Indoor unit actuator
Heating oil return operation
Indoor fan
Thermostat ON unit
OFF
Stopping unit
OFF
Thermostat OFF unit
OFF
Electronic expansion valve of
BP unit
Thermostat ON unit
SH control
Stopping unit
80 pls
Thermostat OFF unit
SH control