A.O. Smith 100 Series Service Handbook page 33

PDB - SECTION C
See Figure 21 on page 28 for location of this section on the PDB.
The upper left corner of the PDB contains the following:
• J1 Socket (Transformer 120 VAC x 24 VAC - 100VA)
• Pin 1 - 24 VAC Common
• Pin 2 - 24 VAC Hot
• Pin 3 - 120 VAC Hot to Transformer
• Pin 4 - 24 VAC Common
• Pin 5 - 24 VAC Hot
• Pin 6 - 120 VAC Neutral to Transformer
• J2 Socket (24 VAC Outputs)
• Pin 1 - 24 VAC Hot to MCB J3 Socket Pin 1
• Pin 2 - 24 VAC Return to MCB J3 Socket Pin 2
• Pin 3 - Ground to MCB J3 Socket Pin 3
• Pin 4 - Not Used
• Pin 5 - Not Used
• Pin 6 - 24 VAC RTN for BMI (Building Management Interface) option
• Pin 7 - 24 VAC for BMI for BMI (Building Management Interface) option
• Pin 8 - Not Used
• Pin 9 - Not Used
• Pin 10 - Not Used
• Pin 11 - Not Used
• Pin 12 - Not Used
C
12 9
11 8
10 7
J2
Figure 24
Servicing should only be performed by a Qualified Service Agent
J1
4 5
1 2
Transformer
3
6
5 2
1
4
24 VAC
Output
6
3
31