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2WAY SYSTEM
Outdoor Unit Repair Procedures
3
9. Compressor
9-1. Compressor Trouble Diagnosis and Check Methods
Generally, compressor failures can be classified into the following categories.
(1) Mechanical trouble
(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 circuit
Trouble diagnosis is based on the following remote controller displays:
A 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
Reference:
Insulation resistance (Use a DC 500 V insulation resistance meter and measure the insulation resistance
between the electrified and non-electrified parts.)
(a) Motor
Min. 300 M
(b) Compressor Min. 100 M (servicing part)
(c) Unit Min. 10 M (This is due to the presence of refrigerant, which decreases
the insulation resistance.)
* Minimum insulation resistance as required by generally accepted requirements is 1 M .
JUDGMENT START
Is there burning of the failed
compressor motor?
Follow the instructions in
“2. Discharging Compressor Oil” and
drain the oil from all compressors in the
same system. Then inspect.
Is the color phase 4.0 or above, or is a
sharp odor present?
Go to “9-2-1. Replacing only the
failed compressor.”
Follow the instructions in
“2. Discharging Compressor Oil”
and drain the oil from the failed
compressor. Then inspect.
Go to “9-2-3. Replacing all
compressors in a system.”
Are there 2 or more outdoor units where
the compressor oil color phase is 4.0 or
higher or where a sharp odor is
present?
Follow the instructions in “9-2-4. Dry
core cleaning” and perform dry core
cleaning of all outdoor units.
Go to “9-2-2. Replacing all
compressors in a failed unit.”
Follow the instructions in
“9-2-4. Dry core cleaning” and
perform dry core cleaning of the
failed outdoor unit.
NO
NO
NO
YES
YES
YES
Reference: Symptoms of motor burning
1. Ground fault results in breaker operation.
2. Short circuit results in different coil resistance at different phases.
3. Open circuit
[H03]
Compressor 1
(INV compressor)
[H11] [H12] [H13]
Compressor 2
(Constant-speed compressor 1)
U-8ME1E81, U-10ME1E81
[H21] [H22] [H23]
Compressor 3
(Constant-speed compressor 2)
U-8ME1E81, U-10ME1E81
U-12ME1E81, U-14ME1E81
U-16ME1E81
CompressorDisplay Not present in model
SM830204-05_2WAY SYS_new.indb 27 15/01/05 15:31:40
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