Takagi T-H3J-DV Service Handbook page 31

WIRING DIAGRAMS (CONTINUED)
Figure 16: Wiring Schematic for 540 (T-H3) Models
W: WHITE
R: RED
G: GREEN
FM
Y
Flame rod
Ground
AFR rod
Gas
Propor-
Valve
Y
Bypass
Valve
Bank of
DIPswitches
Green LED
For instructions on how to use checkpoints during troubleshooting, refer to the water heater's maintenance
sheet. The maintenance sheet is stored in a pouch on the inside of the water heater's front cover.
On-Demand Water Heater Service Handbook for 240, 340 & 540 Condensing Models
BK: BLACK
LB: LIGHT BLUE
BL: BLUE Y: YELLOW
BR: BROWN
O: ORANGE
IG
Igniter rod
R
BL
O
W
O
G
Y
R
W
Note: The two
receptacles below
R
the buttons are
not used.
W
BL
BR
P: PURPLE
540 Outdoor
Heater
Heater
Heater
P
P
PCB
3
9
53
73 G
This receptacle
is used for 540
indoor models
only.
BK
BK
Heat exchanger
BK
thermistor
BK Inlet thermistor
BK Outlet thermistor
540 Indoor
Heater
Y
Heater
Heater
Y
Heater
Thermostat
BK
W
G SW
Ground
Hi-
MV
BL limit
BL
switch
SV1
BL BL
BL
BL
SV2
O.H.C.F
BL
LB
SV3
R
Flow
R
BK Adjust-
Flow ment
R
Sensor
W BK
W
BK
W
BK
W BL
Temperature controller
R BK
540 Indoor Only
W
BK
Temperature remote controller
(optional accessory)
W Exhaust thermistor
W
Hi-limit switch
W W
for exhaust
540 Indoor Only
Y
Y
Y
Y
BK
W
BK
W
Surge
BK
box
W
BK
120 VAC
G
Ground
1
2
Parent
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