Outlet water temperature has exceeded the maximum outlet water temperature.
- 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 for 120 vac to the 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.
- Verify that the boiler pump is set to the proper speed or that the boiler pump is the proper size.
- Replace the main control board.
