Viessmann 100-W WB1B Gas Valve – Pre-Owned | Part No. 7828721

Inconsistent combustion or ignition issues in a Viessmann Vitodens 100-W WB1B boiler — across Heat Only, Combi, System, or Compact configurations — often trace back to a gas valve no longer regulating gas delivery correctly. The Viessmann 100-W WB1B Gas Valve, Part No. 7828721, is the genuine replacement that ensures reliable gas flow regulation for consistent boiler performance.

This is a pre-owned part that has undergone full functional testing to meet quality standards before dispatch, restoring consistent, safe control of gas flow within the boiler.

Compatible Boiler Models

Tested for Quality. Backed by Warranty.

This 7828721 valve helps maintain safe combustion and efficient operation by controlling gas delivery to the burner. Replacing a faulty unit supports optimal heating efficiency and extends boiler life. Supplied with a 6-month warranty for added confidence.

Delivery & Returns

Orders placed before 1:00 PM are dispatched the same day via trusted couriers, with standard or next-day delivery available. Returns are accepted within 30 days if the part is unused and in its original packaging.

Important Safety Note: Please confirm your boiler's exact model and serial number against the compatibility table above before ordering. Gas valves must always be installed by a Gas Safe registered engineer, with a full gas-tightness test before the boiler is returned to service.