Vaillant 438 with 3 zones, frequent S53

[bruce_miranda]

Just to let people know that I wrote to Vaillant to tell them about my boiler and the S.53 that I get on start up sometimes. My boiler was installed in 2010 and they admitted that my PCB may have a fault with it. Later versions were produced with newer software to fix this. Vaillant are sending out a new PCB to me, free of charge.

I have a Vaillant 438 boiler and the PCB has "0020028402 (On a sticker) Then screen printed onto the PCB is: TM-AC1 V132_C1 0020028453 TL-AC PM-03".

Technical department has said the part no for the replacement PCB is 0020036861.

I will try and confirm if the firmware versions are different or not and post that information here too. Will also check the part numbers on the stickers etc.

 

[Dan Robinson]

@Bunnyman?

 

[bruce_miranda]

New PCB has was sent to me has "0020092504 (On a sticker) Then screen printed onto the PCB is: TM-K2 V132_K2 0020080512".

Technical department has said the part no for the replacement PCB is still 0020036861.

 

[bruce_miranda]

OK, so some software has changed. Even the part number of the PCB as seen by the boiler has changed.

Looking via diagnostics the old PCB had a part number of 00 20 02 29 30 and software versions 0402a70802 and 0403ae0512
Looking via diagnostics the new PCB has a part number of 00 20 03 68 61 and software versions 0402a71103 and 0403ae0512

Note the differences between the part numbers as seen via the software as opposed to the ones printed on the stickers and the screen print of the boards.

 

[Dan Robinson]

Firmware updates have a habit of sneaking through in an undetectable way, and it might not be Vaillant who are up to it