Cause of error code A03

Overheat limit open

High Temperature Limit Open (Set Temperature 205°F)

Solution for error code A03

- Check CH, DHW, General Pump Operation
- Assure that there is adequate flow through the boiler by checking the status menu and assuring less than 40°F temperature rise across the boiler.      
- Check thermistor reading on the supply thermistor. Replace it if necessary.