LG LMX25964 Series Service Manual page 58

12-4 Check D
D1. Activate Protection logic Cycle check with protection logic
- We have to check Condenser fan and Freezer fan before performing Check D
- Locked Piston, Current trip and stroke trip can be activated by other problems then the driver or compressor.
~» When process line on compressor is opened, and refrigerant is not expelled
High Pressure : :
8 because it has accumulated in condenser.
pect ted ~> If fauit is corrected after refrigerant is recaptured from sealed system, change
dryer.
Locked piston Low ~» Low side restriction can cause a stroke trip.
, Side »| —» If fault is corrected after refrigerant is recaptured, perform a sealed
Restriction system evacuation and dryer replacement.
~» Check Suction line
~» If refrigerant is overcharged and suction line temperature is lower
than ambient temperature (about 5~10 degrees) or frost is present
150mm from where the suction line enters the compressor..
Over charging
Refrigerant
~» Temp. of compressor and discharge line is normal to slightly higher.
High side pressure is normal to slightly higher than normal
conditions. This is because condenser cannot condense the air
that is trapped in the condenser. The high side pressure and
temperature will not mimic the low side pressures and
temperatures.
Low side
Refrigeration
leak
~» Customer complains of longer run times and poor cooling performance.
~» Lack of refrigerant can, in some incidents, cause piston over travel.
~» Pressure of refrigerant cycle is usually higher than ambient pressure,
therefore oil will flow out with the refrigerant at leak point.
Refrigerant leak
D2. sealed system diagnosis Sealed system
- Check as follows;
Check for Oil leaks
machine compartmen
Yes
Repair leak
at point where
Oi is present,
In/Out Leakage A Welding point
. Comp process stub,
Check for olf 1
Remaining in drip tra' .
Check for Oil leakage Evaporator Replace 2. Comp discharge
at each joint p p Q 3. Hot Line inlet
f the Evaporator Leakage Evaporator .
° P 4. Drier inlet
Check Temp of Dri |
Discharge line 5. Drier outlet ;
and Condenser 6. Evaporator inlet
® 7. Evaporator outlet
8. suction pipe
Frost only
Check frost status ;
Of Evaporator Evaporator inlet Heat Inlet tubing
No "| using heat gun.
\s frost pattern
uniform?
Comp,Cond T >
Ambient temp+5deg Is frost patern
Uniform?
Sealed System
is OK
Sealed System
is OK
@- Heavy repair
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