UPM1 Replacement Kit

UPM1 Replacement Kit (Part No. 8733903903) is a Bosch parts-category service kit intended to replace the UPM1 serviceable assembly in compatible Bosch heating and hydronic systems, helping technicians restore core pump/module functionality without sourcing individual parts. The kit simplifies field maintenance by grouping the routine replacement items into a single service package for professional installers. Specific Bosch North America documentation for part number 8733903903 was not located on official Bosch parts pages; this description is therefore based on the product name and parts-category usage. (bosch-homecomfort.com)