American Standard TCWH-199-AS Installation Start-Up Maintenance Parts page 59

Error Code
Er:70 Register, Ram, Rom, I/O Port, AD Abnormal,
Important EPROM Data or Safe Data Abnormal
Er:72 Flame Signal Detected before Ignition
Er:73 DIP Switch is abnormal
Er:76 Poor Communication
Er:94
Exhaust NTC detects Vent Temperature is Great-
er than 149
Table 24 –Diagnostics and Suggested Corrective Actions
WARNING
found, reset the water heater by pressing the power button. If the error continues to occur, call a qualified
service technician or the gas supplier to check the water heater. Failure to follow these instructions could
result in property damage, personal injury, or death.
Error Code Description
º º
F (65 C)
This water heater is equipped with a blocked vent shutoff system. If Error
Codes Er:29, Er:41, Er: 42, or Er:94 occur, turn off the gas valve at the manual
shutoff. Check the vent terminations for obstructions. If no obstructions are
Possible Remedies
This Error Code will go away when the condition is remedied. If Error
happens again:
1. Turn power OFF and ON at the main power switch internal to the water
heater.
2. If the problem persists, replace the main control.
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 flame 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.
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 require-
ments of the water heater. See dip switch details, this manual, for default
settings.
2. If the problem persists, replace the main control.
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.
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.
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