Cause of error code A10

Communication error E2prom error.

- No communication with the nonvolatile memory in the control board.

Solution for error code A10

- If persistent locking errors, A10 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.