Si33-105 Outline of Control (Outdoor Unit) < Symbols using in this manual >
Function R407C PLUS Series Heat Recovery System 85
Oil return control (cooling) to prevent liquid back flow
PI control
ON/OFF by LP
Oil return
1000 pls (
H
2)
Normal control
According to indoor
unit operation
condition
Oil return, defrost
preparing signal
output
According to indoor
unit operation
condition
Control
according to Tc
SH control
EV1, EV2 (main unit side) = 0pls, EV3 (sub unit side) = 2000pls
PI control
Oil return
preparing flag
Oil return IN
INV
SVP
Outdoor EV
Indoor EV
Outdoor fan
H
3
BS unit
Solenoid valve (20RL)
All 4-way
valve
[C]
Entering Ftc
should be the
upper limit
2 min
(V0810)
Oil return OUT
H
1
· All liquid injection during oil return operation are ON if
compressors are operating
H
1
Oil return operation ending conditions
H
2
Oil return signal only is sent from
Outdoor unit.
H
3
20RH, 20RT are OFF.
OR
DSHi < 20˚C
10 continuous seconds
Th7 – Te < 15˚C
10 continuous seconds
8 minutes elapsed
&
Th7 – Te < 2
OR
1 minute elapsed
(V0810-1)
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