This could possibly be from the zeolite tank for the water softener. Here are links to the zeolite container, the circulation and heat pump, and the drain pump.
Zeolite container- 11028084 Container | Genuine Bosch OEM In Stock
Circulation and heat pump- https://www.appliancepartspros.com/bosch-heat-pump-12008381-ap5984938.html
Drain pump- 00631200 Drain Pump | Genuine Bosch OEM In Stock