Carrier 38VMA Series - Page 32

Table 23 - Indoor Unit Operation
Status
Fan
Electronic Expansion Valve
Thermal ON
ON
ON
OFF
OFF
300P
Thermal OFF OFF 300P
NOTE:
1. First, oil return operation will occur after 140 min from turning the power on to the system.
2.
Next, oil return operation will occur after 8 hours of cumulative compressor operation time.
Table 24 -
Oil Return Operation in Heating mode
Table 25 - Indoor Unit Operation
Status
Fan
Electronic Expansion Valve
Thermal ON
ON
480P
OFF
OFF
480P
Thermal OFF
OFF
480P
NOTES:
1. Oil return operation will occur after 140 min from turning the power on to the system.
2. Next, oil return operation will occur after 8 hours of cumulative compressor operation time.
Table 26 - Defrost Operation
Outdoor Unit Component Pre Defrost Operation Defrost Operation Post Defrost O
peration
Compressor 30Hz + 28Hz 78Hz + 76Hz 30Hz + 28Hz
Outdoor unit fan (FAN A) Normal control OFF Normal control
Outdoor unit fan (FAN B) Normal control OFF Normal control
Four way valve (ST1)
ON
OFF
ON
Electronic expansion valve (EXV A) Normal control 480P Normal control
Electronic expansion valve (EXV B) Normal control 480P Normal control
Electronic expansion valve (EXV C) 0P 480P 0P
Solenoid valve (SV4)
Normal control
Normal control
Normal control
Solenoid valve (SV7) Normal control Normal control Normal control
Ending conditions 75 seconds
T3 > 59⁰F
，
or T > 600 seconds
，
or T4 < 32⁰F, or T3 > 50⁰F 120 seconds
10 seconds
Outdoor Unit Component Pre Oil Return Operation Oil Return Operation Post Oil Return Operation
Compressor 22 Hz + 20 Hz 22 Hz + 20 Hz
Outdoor unit fan (FAN A) Normal control High pressure control Normal control
Outdoor unit fan (FAN B) Normal control High pressure control Normal control
Four way valve (ST1) ON OFF ON
Electronic expansion valve (EXV A
)
Normal control 480P Normal control
Electronic expansion valve (EXV B
)
Normal control 480P Normal control
Electronic expansion valve (EXV C)
0P
80P
0P
Solenoid valve (SV4)
Normal control
Normal control
Normal control
Solenoid valve (SV7) Normal control Normal control Normal control
Ending conditions 75 seconds 120 seconds 55 seconds
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