Cause of error code n02

The fan speed is being limited due to the outlet temperature exceeding 185°F.

Solution for error code n02

- Verify that the system is full of water and that all air has been properly purged from the system.

- Verify that the boiler is piped properly into the heating system.

- Check 120 vac to boiler pump motor on a call for heat. If voltage is not present, check wiring back to the main control board.

- Replace the main control board if necessary.

- If 120 vac is present on a call for heat and the boiler pump is not operating, replace the pump.

- If operating on something other than an outlet sensor, check temperature setting of the main control board.

- Check resistance of water sensors. Replace sensor if necessary.