Instructions / Assembly

AP18733 REV. 3.2.17
70
Error Code Error Code Description Possible Remedies
Er:67 AGM Error
Press the Power button to clear the Error Code.
If Error happens again:
1. Turn power OFF and ON at the main power switch internal to the water heater.
2. Ensure fan inlet hole is completely open after turning the power OFF and ON.
3. Check wiring connections to the AGM. Ensure all are secure.
4. Check AGM operation.
5. Replace AGM components.
6. If the problem persists, replace the main control.
Er:72
Flame Signal Detected
before Ignition
This Error Code will go away when the condition is remedied.
If Error happens again:
1. Check the water heater cover. Ensure it is secure. Flame detection sensor can detect an
external light source.
2. Check ame detection sensor. Ensure connections are secure. Normal operating settings
are more than 2.5DC before ignition, less than 2.5DC after ignition.
3. If the problem persists, replace the main control.
Er:73 DIP Switch is abnormal
This Error Code will go away when the condition is remedied.
If Error happens again:
1. Check dip switches. Ensure switches match the ratings plate requirements of the water heater. See
dip switch details, this manual, for default settings.
2. If the problem persists, replace the main control.
Er:76 Poor Communication
This Error Code will go away when the condition is remedied.
If Error happens again:
1. Check connections from main control to display panel.
2. If the problem persists, replace the display and/or the main control.
Er:78
Cascade Communication
Error
NOTE: This error will only appear in a cascaded system.
1. Turn power OFF and ON at the appliance display panel.
2. If error reappears, ensure all cascaded appliances are powered ON.
3. If error reappears, check Installer Mode parameter 10:Cn at among the both units.
Ensure the setting as “on” in 10:Cn of Installer Mode.
4. If error reappears, check the wire cables into the ‘Main PCB’ connector inside both units.
Ensure the connection of cascade cable between both appliances.
5. If there was no problem wiring connection, replace damaged cables.
6. If the problem persists, replace the main control.
Er:94
Exhaust NTC detects Vent
Temperature is Greater than
149°F/ 65°C
(185°F / 85°C when High
Temp set point is Selected)
This Error Code will go away when the condition is remedied.
If Error happens again:
1. Check if dip switch High Fire setting is ON. Switches 6 and 7 should be OFF for normal operation.
2. Check exhaust temperature sensor. Ensure connections are secure.
3. Check sensor resistance. If resistance is zero, replace the sensor.
4. Check exhaust vent for blockage.
5. If the problem persists, replace the control.
6. If the problem persists, replace the heat exchanger.
Table 29 –Diagnostics and Suggested Corrective Actions