See all products of Spare parts for circulation units for 278-279 series Spare pump UPM3 15-75 for 278HE and 279HE series, with cable. Safety relief valve, 6 bar. Pt1000 probe, Ø6 mm. Spare parts for 2851 and 1522 series. Pt1000 probe pocket, size 1/2” M. Spare flow meters for 278 and 279 series circulation units.