Airwell YCV280, Installation And Maintenance Instructions Manual

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(5) Oil return operation control
1. Entering condition
When outdoor total running capacity is over 25% and less than 75% for 4 hours, or outdoor total running
capacity is less than 25% for 2 hours, the system will enter oil return operation.
* When outdoor total running capacity is over 75% for 10 minutes continuously, the oil return time will
be cleared.
* In defrosting operation, when outdoor total running capacity is over 75% for 5 minutes continuously,
the oil return time will be cleared.
2. Oil return procedure:
All outdoors start up, and run with 75% of total capacity in cooling mode;
In oil return course, outdoor leva1, 2 open to 250pls;
In oil return course, THERMO ON, indoor valves 250pls, THERMO OFF, indoor valves 125pls; when Tdi
or Toil is over 105degree, indoor valve will open larger 10%.
In oil return, Levb OFF.
temp. sensor TA, any outdoor can meet the below conditions for 5 minutes, all the outdoors will enter
defrosting operation.
a. when TE<= -6degree for 5 minutes;
b. when -6<TA<5, -13.6<TE<-6 for 5 minutes, enter defrosting;
c. TA<-6, TE<= -15 for 5 minutes, and compressor has run for 90 minutes between the two defrostings;
In defrosting operation:
a. 4-way valve OFF
b. outdoor motor OFF
c. anti-cold air control of indoor motor OFF
d. outdoor EEV OFF
Quit defrosting
Any of the below conditions can be met, the unit will quit defrosting.
a. After defrosting begins, 10 minutes later, defrosting is over;
b. Detect the defrosting condition of outdoor heat exchanger by TE, all the temperatures at the defrosting
point are over 10 degree for 60 seconds or reaches 15 degree or 10 seconds, quit defrosting;
c. High pressure Pd is over 35kgG/cm2, quit defrosting.
Entering condition:
When the unit has run in heating mode for 33 minutes and the compressor has run for 50 minutes
accumulatively since the last defrosting. By measuring the defrosting sensor TE and outdoor ambient
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