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Error Code Error Code Description Possible Remedies
Er:20
High Limit Overheat
Switch – Closed is Normal,
Open is Fault
Press the Power button to clear the Error Code.
1. Inspect the High Limit Overheat switch. Ensure proper connections.
2. Check High Limit Overheat switch resistance. If resistance is zero,
replace the switch.
3. If the problem persists, replace the main control.
Er:29
APS/Condensate – Closed
is Normal, Open is Fault
(Condensate Drain Trap)
Press the Power button to clear the Error Code.
1. Check APS/Condensate and main controller connections. Ensure all
are secure.
2. Check APS/Condensate resistance. If resistance is zero, replace the
switch.
3. Check APS/Condensate hose. Ensure it is connected and in good
condition.
4. Check condensate line and termination for blockages.
5. Check exhaust vent for blockages.
6. If the problem persists, replace the main control.
Er:31
Water Inlet Sensor Open
or Short
This Error Code will go away when inlet water temperature decreases.
If Error happens again:
1. Check inlet water temperature sensor. Ensure connections are secure.
2. Check sensor resistance. If resistance is zero, replace the sensor.
3. If the problem persists, replace the main control.
Er:32
Water Outlet Sensor Open
or Short
This Error Code will go away when outlet water temperature decreases.
If Error happens again:
1. Check DHW outlet temperature sensor. Ensure connections are
secure.
2. Check sensor resistance. If resistance is zero, replace the sensor.
3. If the problem persists, replace the main control.
Er:33
H/X Temperature Sensor
Open or Short
This Error Code will go away when outlet water temperature decreases.
If Error happens again:
1. Check operating temperature sensor. Ensure connections are secure.
2. Check sensor resistance. If resistance is zero, replace the sensor.
3. If the problem persists, replace the main control.
Er:35
Exhaust Sensor Open or
Short
This Error Code will go away when exhaust temperature decreases.
If Error happens again:
1. Check exhaust temperature sensor. Ensure connections are secure.
2. Check sensor resistance. If resistance is zero, replace the sensor.
3. Check exhaust vent for blockage.
4. If the problem persists, replace the main control.
Er:39
Flame Detected after
Exiting a Flame On
Condition
This Error Code will go away when the false ame 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:40
Gas Leakage continuously
detected for 10 Minutes,
or three times within One
Hour (Greater than 5
Seconds Each Time)
IMPORTANT:
If you smell gas, STOP! Follow the instructions on page 2,
this manual, and call a qualied service technician or the fuel gas utility.
Press the Power button to clear the Error Code.
If Error happens again:
1. Check the water heater cover. Ensure it is secure.
2. Check gas connections for leakage with a soapy solution. Fix any
leaks.
3. Check condition of the burner assembly.
4. If the problem persists, replace the main control.
Chapter3HowtoUseTheControlPanel