Work Procedure After The Backup Operation - Fujitsu AUXB04GALH Service Manual

4-4-2 Work procedure after the backup operation

1. Refrigerant shortage at the backup operation
When excessive refrigerant accumulates in the defective outdoor unit during the backup operation,
it becomes capacity shortage by refrigerant shortage.
The meaning of the sign
LPS : Low pressure sensor detection value
EEV1 : Expansion valve #1
EEV2 : Expansion valve #2
TH2 : Outdoor temperature sensor detection value
TH3 : Suction temperature sensor detection value
TH7 : Heat -Ex.1 gas temparture sensor detection value
TH8 : Heat -Ex.2 gas temparture sensor detection value
TH9 : Heat -Ex.1 liquid temparture sensor detection value
TH10 : Heat -Ex.2 liquid temparture sensor detection value
<How to judge, when refrigerant is deficient>
Refrigerant shortage is judged by the information from "Service tool" during backup operation.
The outdoor unit shall enter the Cooling Main mode or Heating Main mode.
1. On Cooling operation
It often creates "Low pressure protection stop".
>>> When LPS < 14.5psi(0.1MPa) for 10 minutes or When LPS < 7.25psi(0.05Mpa)
If one of this condition happens 5 times within 180 minutes, the system stops permanently.
Running indoor unit's EEV is fully open condition.
>>> It displays corresponding indoor unit's EEV on the chart at the bottom of the monitor.
If there is no sign of closing the EEV from fully opened condition.
2. On Heating operation
It often creates "Low pressure protection stop".
>>> When LPS < 14.5psi(0.1MPa) for 10 minutes or When LPS < 7.25psi(0.05Mpa)
If one of this condition happens 5 times within 180 minutes, the system stops permanently.
EEV1 opens at 480 pulse. (fully open)
EEV2 opens at 480 pulse. (fully open)
Suction superheat is too high, when the condition is following
TH9 < Th7, TH10 < TH8, TH2 TH3
Note: The suctin SH can be larger temprary at the start up, oil recovery, defrosting.
Even if the lowpressure protection does not occur, keep watching the operating condition for a while.
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