The control system has detected over 56,000 ohms from the Temperature Probe on top of the water heater. Check Temperature Probe plug and socket connection…

On/Off is turned off Water heater is not plugged in Tripped Breaker – Blown Fuses 120 VAC power supply problems 24 VAC power supply problems…

Service Notes – Polarity & Ground This water heater is polarity and ground sensitive. The control system will lock out and display a fault message…

The UIM (User Interface Module) is the display on the front of the water heater. The UIM’s major components include a Circuit Board with LCD…

Advanced Diagnostics: Plain english text based diagnostic information (fault messages) on board to help equipment owners accurately describe the reason for a given lock out…

GNITER CURRENT TEST The water heater covered by this Service Manual uses a hot surface igniter (HSI). The control system CCB (page 35) powers the…

To prove burner flame during ignition the control system monitors flame sensing current through the flame sensor. It is a DC micro amp (?A) current…

Air pressure switch testing involves three procedures: • Normal State Test • Operational State Test • Pressure Test Normal State Test Turn off power and…

The control system monitors the “state” of the air pressure switches individually through three separate circuits (see wiring on diagram page 39). The “state” of…

Air pressure switch technical bulletins TB-A023-06 and TB-S023-06 explain air pressure switch construction and test procedures in detail. These technical bulletins are available on the…