Takagi T-H3J-DV Service Handbook page 69

17.2 Insert the end of the cold pipe
into the outlet of the flow
sensor/control valve. See
connection point "D" on page
74 (shown in two places).
17.3 Install these fasteners:
•
One 16A fastener, which
secures the inlet of the flow
sensor/control valve to the
inlet water connection.
See Figure 70. See also
item 461 on page 74.
("16A" is marked on the
end of this clip.)
•
One 14-22 fastener, which
secures the cold pipe to the
flow sensor/control valve.
See item 460 on page 74.
("14-22" is marked on the
end of the clip.)
NOTICE: The cold pipe's
brass ring must be fully
inserted into the flow
sensor/control valve.
17.4 Verify that all of the
fasteners on the water
tubing are installed properly.
17.5 Install the cold water inlet
filter. Refer to the water
heater's manual, if needed.
17.6 Test for leaks by slightly
opening the water supply
to the water heater. Check
the water tube connections
for any drips or leaks. If any
appear, turn off the water,
drain the water heater, dry
the components that got
wet, and fix the leak.
18. Reattach all ceramic pipe heaters
as shown on page 74. (Each is
identified as item 414 or 415.)
On-Demand Water Heater Service Handbook for 240, 340 & 540 Condensing Models
19. Install the fuse box at the location
shown in Figure 41, page 49.
Secure it by hand-tightening both
mounting screws.
20. Reconnect the freeze protection
heater wiring:
•
Connect each male/female pair
of connectors that have YELLOW
wires.
•
When you finish, you will have
reconnected five (5) pair of
connectors with YELLOW wires.
•
Location of each connection:
◦
One near the cold water
inlet
◦
Two near the hot water
outlet
◦
One on the right side,
above the gas valve
◦
One at the top, left-hand
side, along the cold pipe
(item 466, page 74)
NOTICE: All connectors with yellow
wires are connected to the same
circuit, so the order in which you
connect them does not matter.
Figure 71.
Small feet fit into holes.
21. Install the computer board (PCB):
•
Small feet at the bottom must fit
into the corresponding holes in
the case (Figure 71).
•
Insert the screw at the top of the
computer board, then hand-
tighten it to secure the board
to the fuse box assembly. See
Figure 71.
21.1 Connect all of the wires to the
computer board. All of the wire
connectors are uniquely sized
and shaped to fit only in the
correct connector on the board.
If necessary, refer to one
of the schematics on page
30 or page 31.
NOTICE:
•
There are two (2)
receptacles on the
computer board that will
be open (not used).
•
The AFR rod, flame rod,
and ground connections
use a separate wiring
assembly, and that
assembly includes three
wires: yellow, green,
and orange. Install it as
shown in the schematic.
(See page 30 or 31).
•
Be sure to plug the
igniter wires (purple)
into the receptacle at the
top of the PCB.
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