A.O. Smith T-M50 ASME Service Manual page 11

Check-
Parts and Description
point
H1 Gas proportional valve
H2 Flow sensor
Air-fuel ratio rod
I
Flame rod
J Water control valve
K Pump connector
L Heater
M FM port
N Alarm contact
T-M50 / T-M50 ASME Service manual
Color of wires
White - red
Red - Black
White(+) – Black(GND)
Yellow – AFR rod
(Between AFR rod and
the computer board)
Orange – Flame rod
(Between flame rod and
the computer board)
Blue – Brown
Orange – Brown
Red – Brown
White - Black
Black – Black
White - Black
White - Black
11
CONFIDENTIAL
Normal Range
1 to 15 VDC(during operation)
and
20 to 40 Ω
4 to 5.5 VDC
1 to 4 VDC (1,200Pulse/min)
More than 0.5 μA
(during operation)
More than 1 μA (during operation)
13 to 16 VDC
ON: 12.5 to 16 VDC
OFF: 0 to 1 VDC
1 VDC Less ( 0° position)
Less than 1.3 Ω
90 to 110 VAC
Less than 1.3 Ω
Less than 1.3 Ω
Ver. 1.05