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Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
10-20. Freeze protection thermostat
Part#
• 319143-496 (EK184): Indoor
• 319143-497 (EK185): Outdoor
Unit Part#
#713
Function
Temperature detecting device which prevents the pipes within the water
heater from freezing. When this device detects temperatures below 36.5 ˚F
(2.5 ˚C) inside the water r heater, power is supplied to the electric heaters
to prevent the water heater from freezing.
Failure events
1. ON-failure (Always senses freezing temperatures, regardless of actual
temperature).
2. OFF-failure (Never senses freezing temperatures).
Effects on the water heater
if freeze protection
thermostat fails
1. The freeze protection heaters will always be ON, causing heat damage to
components inside the water heater.
2. The freeze protection heaters will never be able to turn on, even under
freezing temperatures, causing freeze damage to the water heater.
Error codes when
the freeze protection
thermostat fails
N/A
Diagnostic
1. Visual inspection: connection/breakage of wires and/or the body has
been broken.
2. Check resistance and voltage: proper range of values shown below.
Color / Number of wires
Black - Black
(itself)
ON mode: 108 VAC - 132 VAC
and less than 1 Ω
OFF mode: less than 1 VAC
and more than 1 MΩ
Checkpoint
B1
Activation and deactivation temperature of the water heater’s freeze protection system
ON mode: 36.5 ˚F (+ 6.3 ˚F - 2.7 ˚F) 2.5 ˚C (+ 3.5 ˚C - 1.0 ˚C)
OFF mode: above 46.4 ˚F above 8 ˚C
7 / 8 " (2 2 .2 m m)
1
-
3
/
8
"
(
3
3
.5
m
m
)
1 / 4 " (5 .7 m m )