Oil Control - Panasonic U-8MF2E8 Service Manual

8. Oil Control

8-1. Oil Level
Oil level Meaning
2 Sufficient
1 Slightly low
0 Extremely low
At the time immediately after the oil level changes from 2 to 1, there is a specified amount of oil in the compressor.
Namely, soon after the oil level is changed to 1, the oil in the compressor is sufficient.
If the oil level "0" indication continues for more than 5 to 10 minutes, it seems short of oil in the system.
Check valves related to oil recovery operation, the refrigerant tubing and for any oil leakage.
8-2. Oil Level Detection
The compressor oil in the crankcase is sent by bypass via a capillary tube to the low-pressure circuit.
The temperature detected by an oil sensor is used to determine whether it is oil (warm) or refrigerant (cold).
8-3. Self-Separator Oil Recovery Control
When a low oil level (1 or 0) is detected, oil is recovered from the oil separator to the compressor though ORVR.
8-4. Inter Outdoor Units Oil Recovery Control – Utilizing Balance Tubes
If the low oil level (1 or 0) continues, that outdoor unit (oil-receiving outdoor unit) receives oil from operating outdoor
units where the oil level is not low (oil-supply outdoor units whose all compressor oil levels are 2).
Control at the oil-receiving outdoor unit begins 30 seconds after an outdoor unit falls into oil level 0.
Control at the oil-receiving outdoor unit begins 120 seconds after an outdoor unit falls into oil level 1.
Oil supply is performed for a maximum of 5 minutes from each unit.
When oil supply is ended, oil supply from that outdoor unit will not occur again for a period of [(No. of outdoor
units minus 1) x 5 minutes]. In addition, oil supply is ended if the oil-receiving outdoor unit oil level changes to 2,
or if the oil-supply outdoor unit oil level becomes "0".
The supply of oil is received from 1 unit at a time, in sequence, according to the order of priority of their inverter
compressors.
Operation during unit refrigerant oil recovery
[A] Oil-receiving outdoor unit
ORVR turns ON and remains ON.
[B] Oil-supply outdoor unit
BPV turns ON and remains ON.
BPV bypass valve repeatedly turns ON and OFF according to a constant cycle.
* This oil recovery might be performed regardless of oil level according to operating condition.
Conditions of oil
The compressor contains sufficient oil.
There will be a risk of oil shortage soon.
The compressor oil is short against
required level for normal operation.
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Control Functions
Judgement
There is no problem.
Confirm that oil is returned after
performing the oil recovery control
operation.
Confirm that oil level is recovered to the
required level after performing the oil
recovery control between systems.
3WAY SYSTEM
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