Control System Hardware; Uim (User Interface Module) - State Water Heaters 120 Series Service Handbook

control system hardware

This section of the manual will provide information on Control System hardware , operation and service
procedures. See Control System operation on page 45 for information on Control System features, navigation,
menus, and user settings.
The water heaters covered in this manual are equipped with an electronic Control System that regulates
water temperature inside the storage tank. Heating cycles and ignition are managed by the Control System.
The ECo (energy cut out), Flame Sensor, pressure switches and Temperature Probe are monitored by the
Control System. The Combustion Blower, Igniter and the 24 Volt Gas Valve are all energized by the Control
System. See Features And Components on page 8 for the location of these components.
components
The main components of the Control System are a uIM (user Interface Module) and a CCB (Central Control
Board). The uIM is located on the top front side of the water heater, see Figure 3 on page 8. The CCB is
mounted on top of the water heater inside a protective enclosure, see Figure 4 on page 9.

UIM (USER INTERFACE MoDUlE)

The uIM's major components include a Circuit Board with LCd display and a Button Pad overlay which
contains the five user input buttons. Figure 36 below shows these components that are located behind the
control interface cover on the front of the water heater.
BUTTON PAD OVERLAY
J3 SOCKET - ENSURE
CABLE IS PLUGGED IN
EXACTLY AS SHOWN
J2 SOCKET - CCB
COMMUNICATION
CAT V CABLE
UIM CIRCUIT BOARD BACK
LCD SCREEN
UIM CIRCUIT BOARD FRONT
Figure 36
Servicing should only be performed by a Qualified Service Agent
J3 SOCKET - BUTTON
PAD COMMUNICATION
37