Fault Code F13 is a Fan Speed Error. The fan is not running at the speed that the control has commanded it to run at. The fan speed had been more than 30% faster or slower than the commanded speed for more than 10 seconds. The red light will display and the word LOCKOUT will flash. This code indicates a serious safety issue and the boiler will not restart until the cause is determined by a technician and he pushes the RESET button on the display. During this lockout fault, the pump will be on as indicated on the second line.

1. Check the combustion air fan wiring.
2. Measure the DC voltage from the red fan wire to ground while it is connected to the fan. It should be between 24 to 40 volts. If it is lower than 24 volts, check for excessive external loads connected to the boiler sensor terminals. Disconnect the 5 pin plug from the fan and check the voltage on the red wire again. If it is now between 24-40 volts, replace the fan. If it is still below 24 volts replace the boiler control board.


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