Oil Control - Panasonic U-8ME2E8 Service Manual & Test Run Service Manual

7. Oil Control

7. Oil Control

(1) Oil Level
Oil level State
2 Sufficient
Possibility of
1
shortage
0 Shortage
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 from 1 to 2, the oil in the compressor is sufficient.
After about 1-hour operation, if the oil level "0" indication continues for more than 5 to 10 minutes, it seems to come
short of oil in the system. Check valves related to oil recovery operation, the refrigerant tubing and for any oil leakage.
(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).
(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 through the ORVR.
(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 or 1).
Control at the oil-supply outdoor unit begins after an outdoor unit falls into low oil level state.
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) × 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.
Solenoid valve control during unit compressor oil recovery
1. Oil-receiving outdoor unit
The ORVR turns ON and remains ON during compressor oil recovery.
2. Oil-supply outdoor unit
The BPV repeatedly turns ON and OFF according to a constant cycle.
* The oil recovery might be performed regardless of oil level.
Conditions of oil level in compressor
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.
Control Functions - Outdoor unit
There is no problem.
Confirm that oil is improved after performing
the oil recovery control operation.
Confirm that oil level is improved after
performing the oil recovery control among
systems.
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2WAY VRF SYSTEM
2WAY SYSTEM
Control Functions
Judgment
1