A.O. Smith ATI-140H-N Service Handbook page 57

5.2 Disconnect the freeze
protec on heater wires.
INDOOR MODELS have 6 sets
of white connectors with yellow
wires (two above the assembly,
three below the assembly, and
one below the secondary heat
exchanger on the right side).
OUTDOOR MODELS have 5
sets of white connectors with
yellow wires (two above the
assembly, and three below the
assembly).
5.3 Remove the screw that
secures the fuse box and
li the fuse box away. (The
last one is not installed on
outside models.)
6. Remove the igniter assembly (item
709, p. 69) from the right-hand side.
See Figure 24, page 35.
7. Slide the black igniter tube off of
the igniter rod. (See "Igniter Rod
Wire Connec on" in Figure 24,
page 35.)
Gas Valve
Port
Air Tube
Figure 66.
8. Remove the Gas Valve and
Manifold Plate Assembly:
8.1 Unplug wire connectors
from the air/fuel ra o rod
(AFR), fl ame rod, and igniter.
See Figure 68.
8.2 Remove the screws that
secure the green ground
wires to the manifold plate.
8.3 Remove the screws that
secure the manifold plate
(Figure 70).
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.
8.4 Remove the screw on the
le side of the gas valve that
secures the power cord.
8.5 Disconnect the clear air tube
off the le side of the gas
valve. (See Figure 66.)
8.6 Disconnect the connector
on the right side (blue wires)
which goes to the overheat
cutoff fuse (Figure 24, page
35).
8.7 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.
8.8 Li the manifold plate/
gas valve assembly upward
to remove it from the gas
Condensing Models: On-Demand Water Heater Service Handbook • 57
Connector/
Nipple
Air Tube
Figure 67.
inlet connec on. (The gas
valve and manifold are s ll
connected together.)
You may need to twist
the gas valve/manifold
assembly slightly.
8.9 Unplug the wire connectors
at the solenoid valve
(SV3); the solenoid valve
is a ached to the corner
of the manifold plate. If
necessary, refer to Figure 72.
Flame Rod Wire Connector:
To remove, pinch flat sides at end
with your finger nails, then slide
connector off the spade.
Figure 68.