Naboo - How do you solve the error message “A64 boiler temperature alarm”?

A64 Boiler high temperature alarm warn that boiler temperature exceeds 150°C/302°F.

As consequence unit deactivate the boiler.

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

Description

Probe SB detect a temperature equal or above 150°C/302°F.

Reset

Errer reset automatically when temperature decrease below treshold.

Checks

Perform following checks:

  • Check current on supply lines; with unit in standby has to be 0A
  • Check C6 contacts have to stay open when unit is off; in case replace C6.
  • Check C4 and C5 (C3 for small units) contacts has to stay open when unit is off or in standby; in case replace them.
  • Check boiler status and no limescale presence.
  • Check level electrodes status.