Serial Number Cutoff for Logic PCB for Bosch Tronic 6000C WH17 & WH27

Bosch Thermotechnology is always upgrading the Bosch tankless water heaters and has recently updated the Bosch Tronic WH17 & WH27.  The new model numbers for these heaters are:

Bosch Tronic 6000C WH17 - Model #45-551721

Bosch Tronic 6000C WH27 - Model #45-557721

There have been several upgrades to the units and one of theses changes is to the Logic Printed Circuit Board (PCB).  The new Logic PCB for the Bosch Tronic 6000C WH17 & WH27 has a different part number from the older units.  Below is the new part numbers and also the serial number cutoff for the PCB boards.

Serial Number Cutoff:

WH17
Logic PCB #8-738-710-921, this would be for any new 6000C WH17 with serial number 555 A 800001 or higher

WH27
Logic PCB #8-738-710-922, this would be for any new 6000C WH27 with serial number 555 A 800271 or higher