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UEZ-IOM (07-23) 1034347-I
Table 28. Circuit Board (DSI Control Module) Display Codes
Display Code Status Display Code Indication
Steady
— Normal operation—no call for heat
0 Ignition sequence active
H Normal operation—call for heat (strong flame)
Flashing
2 Normal operation—call for heat (weak flame)
L Lockout from failed ignition or flame loss
3 Pressure switch is not closed within 30 seconds of venter motor energizing
4 Pressure switch is closed before venter motor is energized
5 Limit switch or rollout open
6 Undesired flame
7 Polarity reversed
Steady Off Internal fault/power failure
TROUBLESHOOTING—CONTINUED
Unit Troubleshooting Using DSI Control Module—Continued
• The SSD on the DSI control module (refer to Circuit Board (DSI Control Module) section) may be used to
troubleshoot the unit. The control module monitors the operation of the heater, and the display indicates normal
operation and various abnormal conditions. If the heater fails to operate properly, check this display (refer to Table
28) to determine the cause and/or to eliminate certain causes. Remove and reapply power to the control module
to view the last five fault codes stored in its memory—the most recent to least recent fault codes will be displayed.