F00 indicates the water in the boiler has overheated. The boiler will not restart until it cools sufficiently and a technician determines and repairs the cause of overheating and pushes RESET on the display. This is a serious safety issue as indicated by the illuminated red light and the word LOCKOUT flashing on the display. During this lockout fault, the pump will be on in an effort to cool the boiler down.
- Check circulator pump operation.
- If the circulator pump is running, ensure there is water in the system and that the water is moving through the system as intended. Ensure that all correct ball valves and or zone valves are open or closed as intended.
- Observe the temperature/pressure gauge. If the water is not too hot and this message is displayed, check the wiring to the water ECO sensor and repair if necessary. If the wiring is ok and this code is still present and the water is not excessively hot, replace the ECO sensor.
