lp-441 Rev. 002 Rel. 008 Date 8.23.18
38
Code
Short Description
Long Description
Corrective Action
F03
High Limit Temperature
Protection
The control shuts down the water
heater after it has met / surpassed
the high temperature limit.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. Check the Dual Temperature Sensor. Ensure it is properly wired to
the control, and that there are no breaks, cuts, or other visible issues
with the sensor wire.
4. Use an ohmmeter to check resistance on first Sensor A, then Sensor
B of the Dual Temperature Sensor.
5. Replace Dual Temperature Sensor if either Sensor A or Sensor B fails
the resistance test. See Figure 26.
Figure 26 - Sensor Detail
F05
Incorrect Fan Speed
The control detects incorrect fan
speed.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. Check condition of wiring.
4. Check Fan PWM connections at control board and fan.
5. Replace fan.
F07
Vent Temperature Too High
The vent temperature has met /
surpassed the maximum limit for
more than 15 minutes.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. Replace sensor.
4. Measure actual vent temperature.
F08
Flame Circuit Failure
The control detects an incorrect
flame level.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. Check ignitor cable connections.
4. Check ignitor cable ground.
5. Replace cable.
6. Check spark gap between spark electrode and burner.
7. Replace ignitor.
F09
Valve Feedback Error
The gas valve does not respond to
controller demands.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again, reset the
water heater and:
3. When water heater attempts to fire, check voltage at the gas valve
connector. If there is voltage, but no gas pressure on the outlet side of
the valve, the valve is stuck closed. Replace the gas valve.
4. If there is no voltage at the ignition phase, replace the control board.
F12
EEPROM Integrity Lockout
The EEPROM check fails. EEPROM
data is corrupted.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. Replace the controller.
F14
Tank Sensor Data Not
Consistent
The data received from the tank
sensors exceeds the difference
allowed by the control.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. Check the Dual Temperature Sensor. Ensure it is properly wired to
the control, and that there are no breaks, cuts, or other visible issues
with the sensor wire.
4. Use an ohmmeter to check resistance on first Sensor A, then Sensor
B of the Dual Temperature Sensor.
5. Replace Dual Temperature Sensor if either Sensor A or Sensor B fails
the resistance test. See Figure 26.
F21
ADC Failure
The ADC test has detected a major
fault in the electronic components.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. If fault code occurs again, replace the controller.
F31
Dual Temperature Sensor B
Error
Dual Temperature Sensor B is out of
normal operating range, meaning
the sensor is either open or shorted.
1. Manually reset the water heater.
2. Observe water heater operation. If fault code occurs again:
3. Check the Dual Temperature Sensor. Ensure it is properly wired to
the control, and that there are no breaks, cuts, or other visible issues
with the sensor wire.
4. Use an ohmmeter to check resistance on Sensor B of the Dual
Temperature Sensor.
5. Replace Dual Temperature Sensor if Sensor B fails the resistance test.
See Figure 26.
