Heat exchanger safety high limit or flue gas temperature limiter has tripped.
- Check flue gas safety high limit and leads for interruptions or shorts, and replace if defective.
- Check heat exchanger safety high limit and leads for interruptions or shorts, and replace if defective.
- Check the operating pressure.
- Check temperature limit; replace if defective.
- Check pump capacitor; replace pump if defective.
- Check PCB fuse, replace if blown (6.3 A fuse according to IEC default).
- Purge the appliance
- Check heat exchanger on the DHW side; replace if clogged.
