This display indicates that the supply temperature of the boiler is excessive. If accompanied by the red FAULT light and LOCKOUT flashing on the display, this code indicates that the temperature on the supply sensor has exceeded 230oF and a serious safety issue exists. The boiler will not restart until the cause of the excessive temperature is repaired by a technician and the RESET button is pushed on the display.
If the FAULT light is not illuminated and this message is displayed, then the supply temperature of the boiler is at or above 210ºF. The message will clear automatically when the temperature drops below 194ºF. During the time that this message or lockout fault is displayed, the pump will be on as indicated on the second line.
- Check circulator pump operation.
- Assure that there is adequate flow through the boiler by accessing the status menu and assuring that there is less than a 50°F rise from the return thermistor to the supply thermistor.
- Check the direction of flow off the boiler circulator. (See Piping Details in this manual.)
- Troubleshoot the thermistor by following steps in F02.
