48 • Condensing Models: On-Demand Water Heater Service Handbook
MAINTENANCE
8.7
Remove the brass 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
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. See
Figure 49.
8.10 Disconnect the solenoid
connectors (Item 707,
p. 69) from the gas
valve. (There are three
connectors.)
8.11 Disconnect the propor onal
gas valve connector (item
711, p. 69) from the
assembly.
8.12 Inspect the gaskets on the
manifold plate for any tears.
If compromised, 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,
p. 69) and gas inlet ring
(item 119, p. 69) on the
gas connec on for cuts or
breaks.
If damaged, replace with
part number 319143-057
(item 151) and/or 319143-
049 (item 119). See page
69.
9. Remove the burner from the
combus on chamber:
9.1
Remove two screws below the
burner, at the back.
(See Figure 48.)
9.2
Remove three screws across
the front of the burner.
(Figure 48.) Do not remove
the screws around the
fl
ame
sensor/AFR and igniter rods.
9.3
Slide the burner out toward
you. You may need to use a
small set of pliers to loosen
the burner on the sides and
then pull from the middle
por on of the inlet holes.
9.4
Check the gaskets on the
burner for any tears. If
there are, replace the gasket
with part number 319143-
032.
10. Disconnect and remove the
following items:
10.1 Disconnect the condensate
drain line (item 415, page
70) from the secondary
heat exchanger assembly
by pulling down. Do not
remove the drain line from
the outlet connec on at the
bo om of the cabinet.
10.2 Remove fastener 16-25
(item 460, page 70) from
the outlet tubing and outlet
water connec on.
Solenoid (SV3)
Terminals
M
anif
old
Plate
Manifold
Plate
Figure 49.
Example:
Install Screws at
Four Locations
Fourth
screw is
on
opposite
side
(not
shown)
Angled View of Primary and
Secondary Heat Exchangers
1
2
3
Vent not included with
outdoor models.
Figure 50.
Front View of Burner Assembly
Three Screws
Three Screws
Two Screws
Area Beneath Burner (Inside Cavity)
Figure 48.