Takagi T-H3J-DV Service Handbook page 40

NOTICE: Remove only the
screws along the outside
edges of the manifold plate.
See Figure 28.
•
DO NOT remove the
screws securing the
manifold plate to the gas
valve.
•
NOTICE: DO NOT remove
the screws along the
interior of the manifold
plate.
5.3 INDOOR MODELS: Remove
the power cord mounting
tab. (Figure 41, page 49.)
5.4 Disconnect the clear air tube
off the left side of the gas
valve. (Figure 29.)
5.5 Remove the brass-colored
screw securing the gas valve
to the gas inlet connection.
The screw is located at the
bottom, right-hand side of
the gas valve. See Figure 41
(p. 49) OR Figure 42 (p.
50).
Manifold Screws:
• DO NOT remove the screws
indicated by the white,
crossed-out circles.
• Remove the screws
indicated by the white
arrows.
Figure 28.
40 • On-Demand Water Heater Service Handbook for 240, 340 & 540 Condensing Models
5.6 Lift the manifold plate/
gas valve assembly upward
to remove it from the gas
inlet connection. (The gas
valve and manifold are still
connected together.)
You may need to twist the gas
valve/manifold assembly slightly.
5.7 If necessary, unplug the
wire connectors from the
solenoid valves, main gas
valve, and proportional gas
valve. (These valves are
connected to the back side
of the gas valve.) There
are five connectors that
can be unplugged from the
manifold plate assembly.
5.8 Inspect the gaskets on the
manifold plate for any tears.
If compromised, replace with
part number 100074229 (item
113) and/or 100074230 (item
114). See p. 73.
5.9 Inspect the o-ring (item 151,
p. 73) and gas inlet ring
(item 119, p. 73) at the gas
connection for cuts or breaks.
If damaged, replace with
Gas Valve
Port
Air Tube
Figure 29.
part number 100074242
(item 151) and/or
100074526 (item 119).
6. Remove the burner assembly
according to the following steps.
6.1 Remove the five (5) pan-
head Phillips screws that
secure the burner to the
combustion chamber. There
are three at the top of the
burner and two more at
the bottom (toward back of
combustion chamber). If
the screws at the bottom
are difficult to remove, lift
the burner while turning the
screws. (See Figure 30.)
6.2 Remove the burner assembly
as described below:
6.2.1 Grasp an oval air vent on
either side of the burner
with a pair of pliers. (See
"Air Vents" in Figure 30.)
6.2.2 Pull firmly to loosen the
burner while bracing it at the
bottom to provide leverage.
6.2.3 Repeat on the opposite side
to loosen the assembly.
Figure 30.
Burner Removal:
Remove one screw at
each arrow location.
(5 total.)