Wiring Diagram Checkpoints For Diagnosis - A.O. Smith T-M50 ASME Service Manual

7. Wiring diagram check points for diagnosis
Check-
Parts and Description
point
A
100 V Power supply
A1
A2,A3 120 V Power supply
B Igniter
C Gas valves
C1 Hi-Limit switch
C2 Overheat cutoff fuse
D1 Easy-link and
Multi-unit link
D2
connectors
E1 Mixing thermistor
E2 Output thermistor
E3 Inlet thermistor
F Remote controller
G Fan motor
Color of wires
White – Black (A)
Brown – Brown (A1)
Black - White
Purple – Purple
Light blue - blue at COM (MV)
Green - blue at COM (SV1)
Orange - blue at COM (SV2)
Red - blue at COM (SV3)
Blue - Blue
Blue - Blue
White - White
Black – Blue
Black – Red
Black - Black
Black - Black
Black - Black
Black - White
Red - Blue
Yellow - Blue
Orange - Blue
10
T-M50 / T-M50 ASME Service manual
Normal Range
90 to 110 VAC
108 to 132 VAC
90 to 110 VAC
78 to 100 VDC (during operation)
/ 0.9 to 1.3 kΩ
78 to 100 VDC (during operation)
/ 1.3 to 1.9 kΩ
78 to 100 VDC (during operation)
/ 1.3 to 1.9 kΩ
78 to 100 VDC (during operation)
/ 0.9 to 1.7 kΩ
Less than 1 VDC
Less than 1 Ω
Less than 1 VDC
Less than 1 Ω
15 VDC
15 VDC
(during Easy-link operation)
See table on p.12
11 to 25 VDC
110 to 160 VDC
13 to 17 VDC
2 to 6.5 VDC
CONFIDENTIAL
Ver. 1.05
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