Replacement Parts And Deliming Products; Combo Heating Inlet And Outlet Side Taps - A.O. Smith 300 Series Installation And Operating Manual

Natural gas and Propane main burner
with igniter assembly for 40k and 45k
BTU/hr models (item 13 in Figure 1).
Flare
Nut
††
34
33
16
41
Figure 3.
Natural gas and Propane (LP) main
burner with igniter assembly for 58k,
62k, 72k and 76k BTU/hr models
(item 13 in Figure 1) †.
Flare
Nut
††
16
34
41
40
Figure 4.
Shown with Junction Box
Cover removed for clarity.
27
28
44
46
45
Figure 5.
10
35
†
36
37
38
39
40
35
†
33
36
37
38
39
26
42
43
47
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Vacuum relief valve install
per local codes (not
supplied with heater).
Figure 6.
Notes:
* Items not supplied with the water heater.
** The side recirculation loop connections may not be
used as the primary water inlet and outlet connections.
See "Combo Heating Inlet And Outlet Side Taps"
below.
*** Caution: harness has 120 VAC during operation.
**** See "Vent Pipe Installation" for more information.
† The orifice on Natural gas models has Right-hand
thread, the orifice on Propane (LP) models has Left-
hand thread.
†† For Natural gas models the Flare Nut has Right-hand
thread. For Propane (LP) models the Flare Nut has
Left-hand thread.

REPLACEMENT PARTS AND DELIMING PRODUCTS

Replacement parts and recommended delimer may be
ordered through authorized servicers or distributors. When
ordering parts, provide complete model and serial numbers
(see rating plate), quantity and name of part desired.
Standard hardware items may be purchased locally.

COMBO HEATING INLET AND OUTLET SIDE TAPS

Models equipped with Combo Heating capabilities are
shipped with the two side plumbing taps OPEN (item 6
and item 9 in Figure 1). See also Figure 7. If the heater
is to be operated without using the side taps for combo
heating, these openings must be plugged with the two
pipe plugs supplied with the heaters.
100304526_2000545240 _Rev. 01