Carrier 38VMH-1P - Oil Return Operation

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Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
29
Oil Return Operation
When cumulative compressor operating time exceeds eight hours, the outdoor unit starts oil return operation.
Table 30 —Oil Return in Cooling Mode
Table 31 —Oil Return in Heating Mode
*1 Fan control for oil return in heating mode.
If T4 ≥ 59°F, outdoor fan step is W2. Otherwise, follow the logic below.
Component Before Oil Return Operation Oil Return After Oil Return Operation
Compressor Normal control
Target frequency for oil return (58Hz
for 38VMB036HDS3-1,66Hz for
38VMB048, 060HDS3-1)
Normal control
Outdoor unit fan Normal control
Four way valve (ST1) OFF
EEV Normal control 300 Pls Normal control
Fast oil return (SV4) Normal control
Hot gas bypass valve (SV5) OFF
Spraying liquid valve (SV6) Discharge temperature protection control
Ending conditions - five minutes -
Component Before Oil Return Operation Oil Return After Oil Return Operation
Compressor
Current value
→30 Hz for two seconds
30Hz for 30sec→
Target frequency for oil return (58Hz
for 38VMB036HDS3-1, 66Hz for
38VMB048, 060HDS3-1)
→30 Hz for 55 seconds, then normal
control
Outdoor unit fan Normal control
Low pressure control
*1
Normal control
Four way valve (ST1) ON OFF OFF for 45 seconds, then switch to ON
EEV Current opening→300P 300 Pls 300 Pls
Fast oil return (SV4) Normal control
Hot gas bypass valve (SV5) OFF OFF Bypass control
Spraying liquid valve (SV6) Discharge temperature protection control
Ending conditions - five minutes six minutes
A210270