110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
33
CONFIDENTIAL
10-17. Freeze protection thermostat
Unit Part #
#713
#710
AOS Part #
319143-185
319143-210
Checkpoint
B1
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 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 the 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: 90 to 110 VAC and less than 1
Ω
OFF mode: less than 1 VAC and more than 1M
Ω
Activation and deactivation temperature of the 110 Indoor’s or 110 Outdoor’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 )
