PACD011001C2 Outline of Control
Function UM Combination “MA1R Series” Using R-407C 433
3.1.9 Oil Equalization Operation
Conducts oil equalization operation at certain time intervals to prevent insufficient oil supply due to uneven
oil distribution when two or three compressors are connected in parallel.
[For 16~20HP model units]
„
The following oil equalization operation is conducted after two STD compressors operates for 2
continuous hours.
„
Oil equalization operation --- Upper-limit frequency is controlled to the following value.
∗
The oil equalization operation is not activated during soft start, oil return operation and defrosting
operation (including defrosting operation preparation) and for 10 minutes after the completion of
defrosting operation and oil return (heating operation).
[For 24~30 class units]
„
The oil equalization operation is conducted in the following steps.
2 min 2 min
16~20HP model
62Hz+OFF 37Hz+ON
STEP1
STEP2
STEP3
STEP3-1
71Hz+ON+OFF
STEP3-2
41Hz+OFF+ON
STEP3-3
71Hz+OFF+ON
STD1 ON
STD2 ON
&
110 cumulative minutes of above operations
TMC time-up
PI control resumes
at 71 Hz + ON + OFF
&
OR
120 sec
60 sec
120 sec
• Thermostat OFF
• Upper limit frequency
at 37 Hz + ON + OFF
• STD1 ON and STD2 ON remain for 30 continuous seconds
• Not in oil return operation (including preparation operation)
• Not in defrosting operation (including preparation operation)
• Elapsed time of 10 minutes or more after oil return (heating operation)
completion
• Elapsed time of 10 minutes or more after defrosting operation
completion
(V0821)