Work Procedure After The Backup Operation - Fujitsu Airstage V-II 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
TH3 : Outdoor thermistor detection value
TH4 : Suction thermistor detection value
TH5 : Outdoor heat EX. temperature sensor detection value
<How to judge, when refrigerant is deficient>
Refrigerant shortage is judged by the information from "Service tool" during backup operation.
1. On Cooling operation
It often creates "Low pressure protection stop" at start up or after oil recovery operation.
>>> When LPS < 0.1MPa at start up, the compressor stops.
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" at start up or after oil recovery operation.
>>> When LPS < 0.1MPa at start up, the compressor stops.
EEV1 of outdoor unit is open at 500 pulse. (full admission).
Suction superheat is too high.
>>> When both TH5
<How to respond, when refrigerant is deficient>
Reuse the refrigerant of the broken master unit.
Connect the high pressure service port of the broken master unit and the low pressure service port of the
substitutional master unit by charging hose, placing the valve on the way.
>>> Refrigerant release from the heat exchanger of the broken master unit.
(Refrigerant is removed until refrigerant shortage is resolved)
Not available to reuse.
>>> New refrigerant is encapsulated.
* substitutional master unit, and encapsulating amount is recorded.
2. Refrigerant charging after the compressor replacement.
When the refrigerant leaks at the time of replacing the defective compressor,
charge the refrigerant as follows depending on the situation.
If the amount of recovered refrigerant is available that was pulled out of outdoor unit
which compressor was replaced.
(When the refrigerant is recovered by refrigerant recovery machine, and its weight is measured.)
>>> Perform vacuuming of repaired outdoor unit thoroughly ,
and add the refrigerant with the recovered amount.
If the amount of recovered refrigerant from outdoor unit that compressor was replaced is not sure.
>>> Once recover all units' refrigerant, and then recharge the calculated amount of
refrigerant again after vacuuming.
TH4 and TH4 TH3.
04-97
Broken Substitutional
master unit master unit
Slave
unit #1