OPERATION & SERVICE
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.
1Only 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 |
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208 VAC | H1 Common & H2 (208) |
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240 VAC | H1 Common & H3 (240) |
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277 VAC | H1 Common & H4 (277) |
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480 VAC | H1 Common & H5 (480) |
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H1 H2 H3 H4 H5 N/A
Primary Winding 
Secondary Winding 
X1 X2
120 VAC
Servicing should only be performed by a Qualified Service Agent
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