Naboo - How do you solve the error message “A11 boiler probe alarm”?

A11 Boiler probe error warn about malfunction of boiler probe SB. 
As consequence unit stop any activity related to the boiler and show the message. 

This message requires the intervention of an authorized technician; causes of the fault must be investigated as per prescriptions.

Description

I/O PCB detect probe signal on inlets 5 and 6 (+) in case circuit is open or in short circuit error will occur. 

Warning

Probes ar K type and generate a direct voltage so will be foundamental observe right polarity when connecting. 
In case of emergency, if part is not available, possible to deactivate the boiler and the water pressure switch PA from Oven model menu

Reset

Error reset automatically when probe is properly connected. 

Checks

Perform following checks: 
- Check SB and his cabling if needed replace it
- Check all other probes; if all defective change I/O PCB.