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

Page: 10 / 91

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