12-8. Failure Display on Outdoor Unit and Correction Method
No. Caused by (outdoor unit) LED lamps
Meaning
Error Detected Points to Diagnose Correction Methods
2 3 4 5
— Normal ●● ●● ●● ●● Normal operation — — —
— Defect in IC chip (E
2
PROM) ●● ●● ●● ●
— Defective Gas Valves ●● ●● ● ●●
A Defective Thermistor 1 ●● ●● ●●
B Defective Thermistor 2 ●● ● ●● ●●
C Limit switch ●● ● ●● ●
D Flame Current Circuit ●● ●●●●
E Lighting failure ●● ●●●
F Lost flame ● ●● ●● ●●
G Incorrect combustion motor speed ● ●● ●● ●
H Over-time period in retry ● ●● ● ●●
I Over number of times in retry ● ●● ●●
J Bypass Valve (V2) not open ●●●● ●●
— Reversing Valve not working ●●●● ●
Gas switching IC (EEP-ROM) data was not
read properly by microcomputer upon
power-on
Electricity applied to GV1 / GV2 while gas
valve is closed
Open / short circuit of Thermistor 1
Open / short circuit of Thermistor 2
Temperature fuse / temperature limiting
switch operated
Flame current detected while combination
gas valve is closed
Fail to ignite by ignition operation (including
retry)
Extinction after flame detection, and does
not re-try (burning after re-try, yet extin-
guishes within 4 minutes)
Inadequate revolution speed
➀ At ignition:
Does not reach 500rpm within 20 sec-
onds
Reaches 500rpm within 20 seconds yet
does not reach prescribed revolutions
(approx. 1,850rpm) within 60 seconds
➁ Less than 500rpm (other than ignition)
Thermistor 1 and/or Thermistor 2 do not
cool down to normal temperature within 10
minutes after being heated up to a speci-
fied temperature (gas is cut off when over-
heating)
Fourth overheating is detected. Retry is
performed up to 3 times when Thermistor 1
and / or Thermistor 2 cool down to normal
temperature within 10 minutes
Thermistor 2 does not detect temperature
increase (approx. xx°F (2°C)) within 30 sec-
onds after ON/OFF valve (RV2) is ON
Thermistor 1 fails to detect temperature
increase (approx. xx°F (1°C)) within 30 sec-
onds after ON/OFF valve (V1) is open at
ignition operation
Can not read IC chip data or miss-
ing IC chip on outside PCB
Detect abnormality in Gas Valve
Circuit at initial checking
Open or Short of Thermistor 1
Open or Short of Thermistor 2
Thermal fuse or Bimetal Thermostat
tripped
Abnormality in Flame Current
Circuit
Could not establish flame
Flame Sensor Circuit detects lost
flame and could not establish the
flame
Incorrect combustion motor speed
Thermistor 1 or Thermistor 2 tem-
perature did not go down during set
period
Combustion stopped by Thermistor
1 or Thermistor 2 more than set
number
Bypass Valve failure or drop-out of
Thermistor 2
Reversing Valve failure, drop-out of
Thermistor 2, or shortage of refrig-
erant
● Confirm proper insertion of gas switching
IC, then reset power supply
● Measure voltage of GV1 (WHT – WHT of I)
and GV2 (ORG – ORG of I) (normal value:
DC0V)
● Measure resistance of Thermistor 1 (BLK –
BLK of M.) (normal value: 6.6±0.5 kΩ at
68°F (20°C))
● Measure resistance of Thermistor 2 (BLK –
BLK of K.) (normal value: 6.6±0.5 kΩ at
68°F (20°C))
● Check continuity of temperature fuse and
temperature limiting switch (YEL – YEL of
P) (normal value: 1Ω or less)
● Measure electric current between BLK of
flame rod and CN17(J) on the PCB (nor-
mal value: 0 µA, combination gas valve
closed)
● Measure electric current between BLK of
flame rod and CN17(J) on the PCB (nor-
mal value: 3 µA or more at ignition)
● Check positioning of ignition plug, flame
rod and burner (normal: electric discharge
gap approx. 4mm)
● Confirm sparking noise at the igniter
As above
● Check revolution of combustion blower fan
● Measure voltage of combustion blower
motor (PLE – PLE of D) (normal value: AC
30 – 115 V)
● Check for refrigerant leaks (pressure in
wide tube while cooling operation: approx.
85.0 PSIG (6 kgf/cm
2
)
As above
● Check position of Thermistor 2.
● Measure voltage at ON/OFF valve (RV2)
(BLK – BLK of F) (normal value: AC 104 –
126 V, ON)
● Check for refrigerant leakage
● Check position of Thermistor 1
● Measure voltage at reversing valve (BLK –
BLK of B) (normal value: AC 104 – 126 V,
ON)
➀ Replace gas switching IC chip
➁ Replace outdoor unit PCB
➀ Replace outdoor unit PCB
➀ Check / modify Connector CN 15 (M)
➁ Replace Thermistor 1
➂ Replace outdoor unit PCB
➀ Check / modify connector CN 16 (K)
➁ Replace Thermistor 2
➂ Replace outdoor unit PCB
➀ Check / modify connector CN12 (P)
➁ Replace thermal fuse
➂ Replace bimetal thermistor
➀ Replace flame sensor probe (CN17)
➁ Replace outdoor unit PCB
➀ Check / modify connector CN17 (J)
➁ Check / modify connector CN7 (G)
➂ Replace ignition electrode
➃ Check / modify insertion of wire on secondary
side of ignition transformer
➄ Replace flame rod
➅ Replace ignition transformer
➆
Replace outdoor unit PCB or power transformer
As above
➀ Check / modify connector CN5 (D)
➁ Check / modify connector CN14 (N)
➂ Replace combustion blower fan motor set
➃ Replace outdoor unit PCB
➀ Repair refrigerant tubes (connections, etc.)
(leaks)
➁ Charge additional refrigerant (leaks)
➂ Replace units
As above
➀ Confirm / modify position of Thermistor 2
➁ Confirm / modify connector CN6 (F)
➂ Replace ON/OFF valve 2 (coil)
➃ Replace outdoor unit PCB
➄ Replace units
➀ Repair refrigerant tubes (connections, etc.)
(leaks)
➁ Charge additional refrigerant (leaks)
➂ Check / modify position of Thermistor 1
➃ Check / modify connector CN03 (B)
➄ Replace reversing valve (coil)
➅ Replace outdoor unit PCB
Note: Failure display remains even after power reset following repairs. The display is overridden upon operation of compressor when heating operation is carried out for a second time after the repair.
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