Worcester Bosch Circulator Pump UPS 15-35-50 130mm 8737710972

The Worcester Bosch 8737710972 is a circulator pump carrying the UPS 15-35-50 designation, built with a 130mm port-to-port dimension and G1 connections for a 230V 50Hz supply. It is the pump that moves primary water around the heating circuit and, on combi models, through the domestic hot water section of the boiler. It is used across the Worcester Bosch Greenstar HE and Worcester HE appliance families.

• The boiler runs but radiators stay cold or heat unevenly, with little or no flow through the system
• The pump is noisy in operation, with rumbling, humming or grinding audible at the casing
• The boiler overheats, locks out or trips on a flow or overheat fault shortly after firing
• Domestic hot water on combi models is intermittent or runs cold when a tap is opened
• The pump head is hot to touch but the pump body is not turning, or the shaft cannot be rotated by hand

• Check the boiler model and serial number against the compatibility list to confirm the pump is the correct fitment
• Confirm the pump designation and port-to-port dimension match the unit being removed, as more than one pump variant is used across the range
• Note the alternative part number 1030600 when cross-referencing an existing order or an old pump label
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.