Vaillant 509119 Connection piece, brass

The Vaillant 509119 Connection Piece is a pipework connector supplied by Vaillant for use within their water heating appliances. It sits in the water circuit and joins pipe runs or components together, holding a secure, sealed joint so flow through the appliance is maintained without loss. Vaillant class the part under adaptors and connectors, which places it among the small fittings that engineers replace when a joint starts to weep or will no longer seal cleanly.

• Weeping or dripping from the joint, with water tracking down the pipework
• Damp staining, limescale trails or corrosion around the connector body
• Pitting or surface breakdown on the fitting, often where the joint has been disturbed before
• A joint that will not seal after reassembly, or a fitting that feels loose on the pipe
• Pressure loss or water loss traced back to the connection point

• Check the appliance model and GC number against the compatibility list to confirm the part suits your unit
• Match the number 509119 against the marking on the existing component before removing it
• Have a suitable washer, seal or gasket to hand, as disturbing an existing joint can damage the seal
• Isolate and drain the appliance before dismantling any part of the water circuit