De Dietrich 81160571 nipple D74/68 H45

Parts of this type are nipples or threaded adapters used to connect boiler components to the pipework, typically for water, gas, or condensate lines. In a boiler system, they create a union between the appliance heat exchanger, manifold, or valve block and the external pipework, ensuring a leak-free joint under operating pressure and temperature. The geometry of such parts is fixed by the appliance design, meaning that manufacturer-specific connection sets — including nipples — are rarely interchangeable with generic components, as the thread type, pitch, seal face, and orientation are matched to the original assembly. When selecting a replacement for such a nipple, a heating engineer should verify the thread type and size (e.g., BSP, NPT, or metric), the material (typically brass or steel), and the sealing method — whether it relies on a flat gasket, O-ring, or taper thread seal. The pressure and temperature rating of the part must be compatible with the circuit it serves. For De Dietrich boilers, the original manufacturer code — such as the one given — is the primary reference, as the dimensions and thread form are specific to the model. Always compare the old part’s physical dimensions — overall length, outer diameter, and thread pitch — before installation, even if the code matches, to avoid misidentification due to catalogue revisions.