Installation - A.O. Smith ATI-140H-N Service Handbook

IMPORTANT: Remove only
the screws along the outside
edges of the manifold plate.
•
DO NOT remove the screws
securing the manifold plate
to the gas valve.
•
DO NOT remove the
screws along the interior
of the manifold plate.
8.2 Remove the screw securing
the gas valve to the gas
connec on. The screw is
located at the bo om, right-
hand side of the gas valve;
see Figure 24, page 35.
8.3 Li the manifold plate/gas
valve assembly upward to
remove it from the gas inlet
connec on. (The gas valve
and manifold plate are s ll
connected together.)
You may need to twist the
gas valve/manifold assembly
slightly.
Figure 78.
Terminals
Solenoid (SV3)
Manifold
Plate
62 • Condensing Models: On-Demand Water Heater Service Handbook
8.4 Unplug the wire connectors
at the solenoid valve (SV3);
the solenoid valve is a ached
to the corner of the manifold
plate. See Figure 78.
8.5 Disconnect the air tube off
the le side of the gas valve.
8.6 Remove the screw on the
le side of the gas valve that
secures the power cord.
8.7 Disconnect the connector
on the right side (blue wires)
which goes to the overheat
cutoff fuse (Figure 24, page
35).
8.8 Disconnect the solenoid
connectors (Item 707, p.
69) from the gas valve.
(There are three connectors.)
8.9 Disconnect the blue wires
from the high limit switch.
See "High Limit Switch (Heat
Exchanger)" in Figure 24,
page 35.
The wires are locked onto the
connectors. Pinch the sides
of each connector to release
it.
8.10 Li the gas valve upward to
remove it from the gas inlet
connec on. You may need to
twist the gas valve/manifold
assembly slightly.
8.11 Remove the wire connectors
from all of the solenoid
valves on the gas valve.
8.12 Inspect the gaskets on the
manifold plate for tears. If
damaged, replace with part
number 319143-044 (item
113) and/or 319143-045
(item 114). See page 69.
8.13 Inspect the o-ring (item 151)
and gas inlet ring (item 119)
on the gas connec on for
cuts or breaks.
If compromised, replace with
part number 319143-057 (item
151) and/or 319143-049 (item
119). See page 69.
Installa on
9. Install the gas valve/manifold
assembly. (See item 102, p. 69.)
9.1 Make sure that the screen on
the inlet to the gas valve is
s ll in place.
9.2 A ach the wire connectors to
each of the solenoid valves.
•
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 79.
Figure 79. Gas Valve Wiring
Solenoid Connector
Stamped Numbered
Number
In each case, these numbers
must match.
Wire