Igniter - A.O. Smith T-M50 ASME Service Manual

10-18. Igniter

Unit Part #
Function
Failure event
Effects on the water
heater if the igniter fails
Error codes when Igniter
fails
Diagnostic
Color/Number of wires
High-voltage igniter cable
14 kVDC
T o H i g h v a l t a g e
i g n i t e c a b l e
P o w e r s u p p l y
A C 9 0 t o 1 1 0 V
#102 AOS Part #
-To ignite the gas/air mixtures when the water heater is ready to burn gas on
its burner surface.
-The output voltage of the igniter is more than 14 kVDC.
1. Unable to ignite during the ignition process.
2. Makes attempts to ignite at all times.
1. The water heater cannot ignite during the ignition process and the "111"
or "121" error codes will display.
2. No effects on the water heater, however, the durability of the igniter
wears down.
111
1. Visual inspection: connection/breakage of wires and/or an observed weak
spark.
2. Check voltages: proper range of values shown below.
Purple(7)-Purple(7)
Igniter
90 to 110VAC
T-M50 / T-M50 ASME Service manual
EKN74
90 to 110 VAC
Purple wire
1 - 3 / 4 " ( 4 4 m m )
33
CONFIDENTIAL
Ver. 1.05
Checkpoint B
121
The high-voltage
igniter cable and
the purple wires
do not come with
EKN74.