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240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
10-12. Thermistors
Part #
*See the table below
Unit
Part#
#407 (Inlet)
#408 (Outlet )
#411 (Heat exchanger)
Function
Measures cold/hot water temperatures in the water heater.
Failure events
Unable to properly measure water temperatures within the water heater.
Effects on the water heater
if thermistor fails
If the thermistors fail open or short, error code appears before starting
operation. If resistance values are just off, The water heater will have
temperature fluctuations in hot water.
Error codes when
thermistors fails
311 (Outlet) 321 (Inlet) 331 (Heat exchanger)
Diagnostic
1. Visual inspection: connection/breakage of wires and/or debris on
thermistor.
2. Check voltages and resistance; proper range of values shown below.
Color / Number of wires
Inlet Black (42) - Black
68 ˚F (20 °C) 9.0 to 13 kΩ
122 ˚F (50 °C) 3.3 to 4.4 kΩ
176 ˚F (80 °C) 1.4 to 1.8 kΩ
(see table below for
more resistance values)
Check
point
*See the
table
below
Heat exchanger
Black (12) - Black
Outlet Black (113) - Black
NOTE:
Pictures are on the following page
Part #
Description
Checkpoint
Model
319143-214 EKK4J
Inlet thermistor
E2
240 (T-H3J) / 340 (T-H3S)
319143-465 EK137
Inlet thermistor
E2
540 (T-H3)
319143-529 EK207
Outlet thermistor
E1
240 (T-H3J) / 340 (T-H3S)
319143-190 EKK1A
Outlet thermistor
E1
540 (T-H3)
319143-096 EKK2T
Heat exchanger thermistor
E3
540 (T-H3)
*