List Of Main Components In The Interior View - A.O. Smith Water Heater 520 Direct Vent Indoor Service Manual

4. List of main components in the interior view

No. Description
Manifold assembly with
1
gas valve assembly
2 Computer board
3 Igniter
4 Transformer
5 Water inlet
6 Water outlet
7 Mixing thermistor
8 Inlet thermistor
9 Output thermistor
10 Overheat cut-off fuse
Burner assembly
11
(Burners)
12 Hi-limit switch
13 Fan motor
Freeze protection
14
thermostat
15 Flow sensor
Primary heat exchanger
16
assembly
17 Gas inlet
18 Pipe heater
19 Water control valve
Secondary heat
20
exchanger
520 Indoor / 520 Outdoor Service Manual
Item# in
components
diagram
319143-046 (LP model)
118
319143-047 (NA model)
701
123
702
411
435
418
422
433
404
101
432
114
704
719
429
401
456
121
426
423
446
8
AOS Part #
319143-126
319143-052
319143-127
319143-074
319143-098
319143-081
319143-085
319143-096
319143-067
319143-030
319143-095
319143-043
319143-129
(520 Indoor)
319143-144
(520 Outdoor)
319143-092
319143-064
(510 Indoor)
319143-118
(510 Outdoor)
319143-050
319143-089
319143-086
319143-108
CONFIDENTIAL
Ver. 1.00
Common parts
For other models
110, 310, 510, 910, 710
910
710
710
710
510, 910, 710
510, 910, 710
510, 910, 710
310 Indoor, 510 Indoor,
910, 710
910, 710
110, 310, 510
910, 710