Vaillant Reducing Ring A/B/C/D 194178

The Vaillant Reducing Ring A/B/C/D is a sealing component supplied under manufacturer part number 194178. It is listed for Vaillant gas boilers in the Thermocompact, Turbomax Plus and Turbomax Pro ranges, where it forms part of the pipework or component joint sealing arrangement. The A/B/C/D designation indicates the ring is used across more than one connection size or position within these appliances.

• Weeping or visible water traces at the joint the ring seals
• Staining, crusting or limescale build-up around the connection
• The ring has hardened, flattened or cracked with age and no longer seals under pressure
• Persistent pressure loss traced to a joint on the affected appliance
• Water marks appearing below the boiler casing after the appliance has run

• Check the appliance data plate and confirm the exact model and variant, including the R revision suffix
• Confirm the ring designation required for the joint being worked on, as the part covers A/B/C/D positions
• Compare the existing ring against the replacement to confirm it is the correct item for the connection
• Isolate the appliance and follow the manufacturer's guidance before opening any gas or water path