High temperature limit exceeded
- Check circulation pump operation.
- Assure that there is adequate flow through the boiler by accessing the status menu and assuring that there is less than a 50ºF rise from the return thermistor to the supply thermistor.
- Check thermistor reading on supply thermistor. Replace switch if faulty.
- Disconnect the two wires from the thermostat terminals and connect the wires together. Depress the S4/Reset button. If the fault clears, the problem is outside the boiler.
