Freeze Protection Heaters - A.O. Smith T-D2-OS Service Manual

10-14. Freeze protection heaters

Unit Part #
Function
Failure events
Effects on the water
heater if heater fails
Error codes when
heaters fails
Diagnostic
Color/Number of wires
The water heater has two types of the heaters in it. The one is for protecting of the heat
exchanger and the outlet pipe, the other one is for protecting of the inlet pipe.
For the heat exchanger
(Part# 414 / EKK2R)
#414
Takagi Part #
#415
Prevents the heat exchanger, water valves, and water pipes within the water
heater from freezing. The heaters are but one of the freeze protection
devices in the water heater.
Open circuit failure: Ceramic heaters do not receive the voltage needed to
heat up.
Ceramic heaters do not activate, allowing water contained in the heat
exchanger to freeze up, possibly causing the heat exchanger to burst.
1. Visual inspection: connection/breakage of wires and the condition of the
heaters.
2. Check: whether those are in the normal range as shown in the following
table.
Black - Black 90 to 110 VAC (during freeze protection operation)
For the outlet pipe
T-D2-IN / T-D2-OS Service Manual
EKK2R
EKK2P
N/A
For the inlet pipe
(Part# 415 / EKK2P)
30
CONFIDENTIAL
Ver. 1.00
Checkpoint B1