A.O. Smith 110 Indoor Service Manual page 38

Error Code
7 Check if there is dust and lint in burner and heat exchanger, when the water
heater has been installed in laundry room.
10
8 Check if there is grease and dirt in burner and fan motor, when the water
heater has been installed in restaurant.
9 Check the manifold pressure in the water heater.
Error Code
Ignition failure
11
1 Check gas supply and inlet gas pressure (Refer to section 1)
2 Check the igniter (Refer to section 10-16)
V isual inspection: connection/breakage of wires and/or observed weak
Error code is
spark.
[1] Cracks/soot on igniter rod
shown after
[2] Improper gap between burner & igniter rod
three failed
Normal gap: 0.16" (4mm)
attempts at
[3] PCB fault
ignition Normal: 90 to 110 VAC at #7 (purple-purple) (during ignition)
[4] Igniter fault
3 PCB fault
[1] No voltage to main gas solenoid valve (MV)
Normal: 78 to 100 VDC between COM (blue) & #3 (light blue)
(during operation)
[2] No voltage to gas solenoid valve (SV
Normal: 78 to 100 VDC between COM (blue) & #53 (orange)
(during operation)
[3] No voltage to gas proportional valve (VG
Normal: 1 to 15 VDC between white & red (during operation)
4 Gas solenoid valve fault
[1] Main gas solenoid valve (MV) fault
Normal: 0.9 to 1.3 kΩ between COM (blue) & #3 (light blue)
[2] Gas solenoid valve (SV
Normal: 1.3 to 1.9 kΩ between COM (blue) & #53 (orange)
[3] Gas proportional valve (VG
Normal: 1 to 15 VDC between white & red (during operation)
5 Disconnected/damaged O.H.C.F.
V isual inspection: connection/breakage of wires.
Normal: 1 Ω or less between blue & blue
Malfunction description
) fault
2
) fault
0
110 Indoor / 110 Outdoor Service Manual
Diagnosis
Turn off the power or water supply
Diagnosis
)
2
)
0
(Refer to section 10-12)
38
CONFIDENTIAL
Ver. 1.01
Checkpoint
Cancellation method
Checkpoint
B
C
H1
C
H1
C2