Wilo Star ZRS 12/2-3 KU C
These pumps were used in Bosch Heat Pump, however they are no longer available.
The Wilo Star ZRS 15/6-3 can be used as a replacement for this pump. You will also require the 25mm Loose Nut x 20mm Male Pump Union as the old pump had a 20mm thread and these pumps have a 25mm thread.