Rheem RTGH-RH10DV - Page 54

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Error Code Error Code Description Possible Remedies
Er:66 Mixing Valve 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. Check wiring connections to mixing valve. Ensure all are secure.
3. Replace mixing valve.
4. If the problem persists, replace the main control.
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
Chapter3HowtoUseTheControlPanel