EdgeStar CWB8420DZ - Diagnostic Guide by Symptom

9.2 Diagnostic Guide
Remember, before entering the sealed system, all other systems must be tested and properly
repaired. These include the electrical, control and air flow systems. Before "turning a
screwdriver", many checks can be made simply by using your senses:
LISTEN:
 What is the customer complaint?
 Are the fans operating?
 Is the compressor operating?
LOOK:
 Does the light button turn the light on and off?
 What is displayed on the control panel?
 Are the controls set properly?
 Do door gaskets seal properly?
TOUCH:
 Is air circulating though the bottom grille?
 Is air circulating in the compartments?
 Is the suction line to the compressor cool?
 Is the discharge line from the compressor hot?
 Is the condenser hot?
 Is the hot pipe hot?
SYMPTOM
DIAGNOSIS
For models - Dual zone with single door (CWB8420DZ)
The displayed temperature is
higher than the set temperature
in the upper zone.
1. Is the ambient temperature too high (more than 35°C)?
2. Is the ventilation blocked?
3. Is the evaporate fan motor in the upper zone defective?
4. Is the condenser fan motor defective?
5. Is the temperature sensor defective?
6. Is the cooling system defective?
The displayed temperature is
lower than the set temperature in
the upper zone.
1. Is the lower zone temperature normal? Otherwise check the PTC
heater and fan motor in the lower zone.
2. Is the fan motor in the middle partition defective?
3. Is the temperature sensor defective?
4. Is the Main PCB or Display PCB defective?
5. Is the ambient temperature too low (less than 0°C)?
The displayed temperature is
higher than the set temperature
in the lower zone.
1. Is the upper zone temperature normal? Otherwise check the
upper zone problem first.
2. Is the fan motor in the middle partition defective?
3. Is the temperature sensor defective?
4. Is the ambient temperature too high (more than 35°C)?
The displayed temperature is
lower than the set temperature in
the lower zone.
1. Is fan motor defective?
2. Is the PTC heater defective?
3. Is the temperature sensor defective?
4. Is the Main PCB or Display PCB defective?
5. Is the ambient temperature too low (less than 0°C)?