Panasonic U-72MF2U9 Service Manual

Also see for U-120MF2U9: Installation instructions Operating instructions Installation instructions Technical data

Contents

2 - 231234567893WAY VRF SYSTEMOutdoor Unit Repair Procedures9. Compressor2WAY VRF SYSTEMOutdoor Unit Repair Procedures9. Compressor9-1. Compressor Trouble Diagnosis and Check MethodsGenerally, compressor failures can be classified into the following categories.(1) Mechanical trouble →(1) Motor → Min. 300 MΩ(2) Compressor → Min. 100 MΩ (servicing part)(3)* Minimum insulation resistance as required by generally accepted requirements is 1 MΩ.Unit → Min. 10 MΩ (This is due to the presence of refrigerant, which decreases theinsulation resistance.)(A) Locking (intrusion of foreign objects, galling, etc.)(B) Pressure rise failure (damaged valve, seal, bearing, or other component)(C) Noise (damaged stator rotor, valve, or other component)(2) Electrical trouble → (A) Coil burning(B) Open circuit(C) Insulation failure(D) Short circuitTrouble diagnosis is based on the following remote controller displays:Reference:Reference: Symptoms of motor burning1. Ground fault results in breaker operation.2. Short circuit results in different coil resistance at different phases.3. Open circuitInsulation resistance (Use a DC 500 V insulation resistance meter and measure the insulation resistancebetween the electrified and non-electrified parts.)[P16] [P29] : 1st compressor, right side when viewed from front[P19] [P26] : 2nd compressor, left side when viewed from frontA judgment is made based on factors that include the following: coil resistance (varies depending on the compressor),insulation resistance, current, leakage breaker operation, oil and refrigerant fouling, odor, pressure, and noise.NONONOYESYESYESIs there burning of the failedcompressor motor?Go to “9-2-1. Replacing only thefailed compressor”.Follow the instructions in“2. Discharging Compressor Oil”and drain the oil from the failedcompressor. Then inspect.Go to “9-2-2. Replacing allcompressors in a failed unit”.Follow the instructions in“9-2-4. Dry core cleaning” andperform dry core cleaning of thefailed outdoor unit.Is the colorphase 4.0 or above, or is asharp odor present?JUDGMENT STARTFollow the instructions in “2. Discharging CompressorOil” and drain the oil from all compressors in the samesystem. Then inspect.Follow the instructions in “9-2-4. Dry core cleaning”and perform dry core cleaning of all outdoor units.Go to “9-2-3. Replacing all compressors in a system”.Are there 2or more outdoor unitswherethe compressor oil color phase is 4.0 orhigher or where a sharp odor ispresent?