Cause of error code A09

Internal software err ram error

- The software is not operating correctly.

Solution for error code A09

- If persistent locking errors, A09 occur, systematically disconnect all wires not supplied by the factory with the exception of the power supply (CH T’Stat, DHW T’Stat, LWCO, Pumps, etc.). If the error code goes away, determine which circuit may be introducing electrical noise or feedback. 
- If the error persists after all these wires are disconnected, contact your PB Heat representative. 
- If this error occurs after replacing a control, contact your PB Heat representative.