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OPERATION & SERVICE
Servicing should only be performed by a Qualified Service Agent
34
TRANSFORMERS
This section of the manual provides information on how to test and ensure the multiple tap
120 VAC Control Circuit Transformer is wired properly on Electronic Control Models. This
section will also provide test procedures for the 24 VAC transformer used by the electronic
control system - see Figure 2 on page 9 for location of the transformers on these models.
Surface Mount Control Models are not equipped with transformers.
120 VAC Control Circuit Transformer Wiring
The 120 VAC Control Circuit transformer is a multiple or “multi” tap transformer that can
accept 4 different input voltages to it’s primary winding. See Figure 2 on page 9 for location.
This transformer outputs 120 VAC power from it’s secondary winding which powers the CCB
circuit board and the contactor coils. The input power wiring to the primary winding of this
transformer must be configured to match the power supplied to the water heater. Incorrect
wiring can cause output voltage from the transformer’s secondary winding to be too low or
too high. This can cause “contactor chatter” (contacts open and close rapidly) and may
permanently damage the contactors and/or the CCB circuit board. The table and illustrations
that follow show how to properly configure the input power wiring to the transformers primary
winding.
1 Only one wire need be changed on the transformer to change voltage. Do not move or change the wire to
the common H1 connection on the primary winding or either wire to the secondary winding X1 or X2
connections. Remove the wire from the terminal marked H2 208, H3 240, H4 277 or H5 480 and attach it to
the appropriate terminal that matches the water heater’s power supply voltage.
WATER HEATER POWER SUPPLY VOLTAGE PRIMARY WINDING CONNECTIONS
208 VAC H1 Common & H2 (208)
240 VAC H1 Common & H3 (240)
277 VAC H1 Common & H4 (277)
480 VAC H1 Common & H5 (480)
H1 H2 H3 H4 H5 N/A
Primary Winding
Secondary Winding
X1 X2
120 VAC