A.O. Smith T-D2-OS User Manual

T-D2-IN / T-D2-OS Service Manual
Ver. 1.00
30
CONFIDENTIAL
10-14. Freeze protection heaters
Unit Part #
#414
#415
Takagi Part #
EKK2R
EKK2P
Checkpoint B1
Function
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.
Failure events
Open circuit failure: Ceramic heaters do not receive the voltage needed to
heat up.
Effects on the water
heater if heater fails
Ceramic heaters do not activate, allowing water contained in the heat
exchanger to freeze up, possibly causing the heat exchanger to burst.
Error codes when
heaters fails
N/A
Diagnostic
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.
Color/Number of wires Black - Black 90 to 110 VAC (during freeze protection operation)
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.
4-3/8" (110mm)
2-3/4" (70mm)
3-1/2" (90mm)
13" (330mm)
1" (25mm)
3/8" (10mm)
7-1/8" (180mm)
(Part# 414 / EKK2R)
For the outlet pipe
For the heat exchanger
(Part# 415 / EKK2P)
For the inlet pipe

A.O. Smith T-D2-OS Specifications

General

Brand	A.O. Smith
Model	T-D2-OS
Category	Water Heater
Language	English