American Water Heater STCE3-52/80/119 ユーザーズマニュアル

Servicing should only be performed by a Qualified Service Agent

34

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.

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.