T-D2-IN / T-D2-OS Service Manual
Ver. 1.00
32
CONFIDENTIAL
10-16. Transformer
Unit Part #
#702
Takagi Part #
EKH09
Checkpoint
A1,A2
Function
-To transform input voltage from 120 to 100 VAC.
-Every electrical component of the water heater is designed to only work
with a 100 VAC power supply, therefore, the water heater comes equipped
with this transformer.
Failure events
1. There is no power coming from the transformer.
2. The voltage from the power supply cannot be converted to 100 VAC.
Effects on the water
heater if transformer fails
1. The water heater does not operate due to lack of power from
transformer.
2. A failed transformer can cause electrical damage to other electrical
components within the water heater.
Error
codes
when
transformer fails
N/A
Diagnostic
1. Visual inspection: connection/breakage of wires and/or signs of electrical
damage.
2. Check voltages of the transformer: Proper range of values shown below.
Color/Number of wires
White – Black
120 VAC / less than 1
Ω
Brown – Brown
100 VAC / less than 1
Ω
Brown - Brown
To power computer
board and heaters
(100 VAC)
White - Black
From the 120 VAC power supply
T D 1- 2 2 7
1 2 0 V 1 0 0 V
2 - 3/ 8 " ( 6 1m m )
2
-
3
/
4
"
(
7
0
m
m
)
1
-
1
/
2
"
(
3
7
m
m
)
3 - 3/ 4 " ( 9 4m m )
5 - 7 /8 " (1 5 0 mm )
5- 7 / 8" ( 1 50 m m )
