A.O. Smith ATI-140H-N Service Handbook page 51

4.2 Line up the holes, then insert
and hand- ghten two (2) hex
head screws (item 54). See
page 69.
5. Secure the heat exchangers to the
case:
Insert and hand ghten three
(3) moun ng screws as shown
in Figure 25, page 36. This
will secure the heat exchanger
assembly to the heater case.
6. Install the burner into the combus on
chamber. (See page 70.) There are
grooves on the sides of the combus on
chamber; the bo om of the burner will
slide along the grooves.
6.1 Insert and hand ghten two
(2) screws below the burner,
at the back. (See Figure 48,
page 48.) These screws
will secure to the back of the
cabinet. You may need to
push the assembly up some
in order to line up the holes.
Gas Valve
Port
Air Tube
Figure 56.
6.2 Insert and hand ghten three
(3) screws along the top,
front por on of the burner.
See Figure 48, page 48.
7. Insert the outlet tubing into the
water outlet connec on, making
sure that the brass ring on the
tube goes all the way in and is
fl ush with the top of the outlet
connec on. (Figure 54.) Install
fastener 16-25 (stamped on the
end of the fastener). See also item
460 on page 70.
8. A ach the top of the condensate drain
tube to the port on the bo om of the
secondary heat exchanger. See Item
415 and connec on point "E" on p.
70.
9. Install the manifold plate/gas valve
assembly (item 102, p. 69) to the
combus on chamber:
9.1 Make sure the screen on the
inlet to the gas valve is s ll in
place.
Solenoid Connector
Stamped Numbered
Number
In each case, these numbers
must match.
Figure 57. Gas Valve Wiring
Condensing Models: On-Demand Water Heater Service Handbook • 51
9.2 A ach the wire connectors to
each of the solenoid valves.
•
•
•
•
9.3 Slide the gas valve/manifold
plate assembly onto the gas
inlet connec on. You may
need to rotate the gas valve
while sliding down for an
easier fi t. The tab on the gas
valve connec on should line
up behind the tab on the gas
inlet connec on.
9.4 Secure the gas valve to the
gas inlet by installing the
brass screw (with washer)
through both tabs at the
connec on. Hand-tighten
only. See Figure 25, page
36.
9.5 A ach the air tube from the
bo om of the combus on
Wire
chamber to the port on the
le side of the gas valve.
(See Figure 56 and Figure 52,
page 49.)
Each connector has a dark
blue wire, except for the
proportional valve. The
other wire colors will vary.
Each set of wires has a
tag with a number on it.
Each solenoid valve has
a number stamped next
to it. During installation,
each wire number must
match its solenoid valve
number. See Figure 57.
Install each connector to
the solenoid valve with
the matching number.
The proportional valve
does not have a number
and is located at the
bottom of the assembly.
Wire colors: red & white.