Contactor Configurations - A.O. Smith dre-52 Service Handbook

Contactor Configurations

This illustration shows how contactors are configured and how they provide power to the
heating elements on Electronic Control Model water heaters, This is a redundant contactor
configuration - two contactors must close their contacts to energize any heating element.
Elements and Banks are numbered according to how the control system monitors them -
see Element Sensors pages 27 and 28. There are two contactors installed for each Bank.
IE: the illustration shows a 9 element configuration, a water heater factory equipped with 6
heating elements would have 4 contactors and a water heater with 3 elements would have 2
contactors. Wiring is shown for the first two heating elements in Bank 1 only for simplicity.
BANK 1 (LOWER)
1 2 3
Blk Blk Blu
Servicing should only be performed by a Qualified Service Agent
OPERATION & SERVICE
BANK 2 (MIDDLE)
1 2 3 4 5
Red Yel Red Blk Blk Blu
7
8
4
5
1
2
Contactors
4 5 6
Blk Blk Blu Red Yel Red
Element Numbers/Connections
Wire Colors to Elements
6 4 5 6
Red Yel Red
9
BANK 3 (UPPER)
6
BANK 2 (MIDDLE)
3
BANK 1 (LOWER)
Heating Elements
Heating Element Banks
4 5 6
LEGEND
30
BANK 3 (UPPER)
7 8 9 7 8
Blk Blk Blu Red Yel Red
Power
Connection
Terminals
9