Z10025340 PRINTED CIRCUIT BOARD (Z542122). The printed circuit board is a boiler's central electronic control. The printed circuit board controls every function via the thermostats, switches and sensors. This ensures the boiler runs safely, preventing the boiler from working if any internal faults are detected. Designed for the Vokera Compact 25 29 and 35 HE, Rain 24 28 and Sabre 25 29 HE Boilers. Genuine brand new NSS product, covered by a NSS manufacturer's guarantee.