Cause of error code Er78

Cascade Communication Error

Solution for error code Er78

NOTE: This error will only appear in a cascaded system.

- Turn power OFF and ON at the boiler display panel.
- If error reappears, ensure all cascaded boilers are powered ON.
- If error reappears, check Installer Mode parameter 28 at the Master boiler. Ensure the number of cascaded units chosen in this parameter matches the number of cascaded units in the system.
- If error reappears, check Installer Mode parameter 27 at all cascaded boilers. Ensure the address number matches that of the connected boiler (00 for Master, 01 for Follower 1, etc.) and that no numbers are skipped or repeated.
- Ensure every unit in the cascade system is connected properly. Inspect the cascade cables and ensure all are connected without damage or defect. Repair or replace any damaged cables.
- If the problem persists, replace the main control.