Worcester Greenstar Gas Valve 848 Sigma – Pre-Owned | Part No. 871860004A0

Ignition failure, flame instability, or inconsistent heating output in a Worcester Greenstar i Combi or i System ERP boiler often points directly to a faulty gas valve. This precision component controls the flow of gas to the burner — when it fails or drifts out of calibration, combustion performance drops and the boiler can lock out entirely. The Worcester Greenstar Gas Valve 848 Sigma (Part No. 871860004A0) is the correct replacement, restoring accurate gas regulation and stable, safe combustion across the compatible Greenstar i range.

This pre-owned unit has been removed from a fully functioning boiler and tested by our qualified engineers to confirm reliable performance. It fits the Greenstar 25i and 30i Combi ERP, plus the 9i through 24i System ERP and 27i/30i System Compact ERP models, including LPG variants. Supplied with a 6-month warranty.

Compatible Boiler Models

Tested. Reliable. Warranted.

Every pre-owned gas valve we supply is removed from a working boiler and tested by our experienced engineering team to verify proper gas regulation and safe operation. This 871860004A0 unit resolves ignition faults and heating instability caused by a failing valve in Worcester Greenstar i series boilers. Supplied with a 6-month warranty. A brand-new version with a 12-month warranty is also available — please enquire.

Delivery & Returns

Orders placed before 1:00 PM (Mon–Fri) are dispatched the same working day, with standard and next-day delivery options at checkout. Returns are accepted within 30 days in original unused condition.

Note: Please confirm that part number 871860004A0 matches your existing gas valve before ordering. Installation must be carried out by a Gas Safe registered engineer to ensure safety compliance and warranty validity.