Practika A09 alarm

There have been instances reported of Practika boilers displaying alarm code A09 (Smoke Sensor fault) where no such component or alarm exists on the product (the Practika uses a photoresistor sensor to determine the presence of ignition rather than smoke temperature). Other alarms, not related to the product, or raised when no fault condition occurs, might also be observed.

It has been established that there may in these cases be interference induced on the ribbon cable connecting the motherboard to the control panel due to its length. The result of this is to affect the motherboard such that the boiler takes on some characteristics / software configuration of a related product with which it shares the same board (Variomatic, which does use a smoke sensor).

To resolve this,  MCZ have recently producted two separate motherboards for the two products; The Practika board now only contains software for that product so cannot adopt the identity of another peoduct under these conditions. Specflue code to purchase/reorder: 52MOTH8600.