MK4 - Replacement Regulator Diaphragm and Seat Assembly (MKIV)

Complete assembly: diaphragm, seat and seat cap.

Once installed, this assembly is fully encapsulated (sealed unit).

This reduces the risk of contamination and lowers the risk of pressure creep (progressive pressure increase).

The fully encapsulated design also means that if the regulator is serviced in an environment that is not perfectly clean, the risk of introducing contaminants into this sealed assembly is greatly reduced.

Main reasons to replace these parts on your regulator:

• - A gas leak through the diaphragm (extremely rare).
• - Wear of the diaphragm’s peripheral gasket (also very rare).
• - A pressure creep issue — this is the most common reason to purchase this assembly.

Regulator Pressure Creep

Creep is generally caused by contamination entering the regulator’s seat and seat cap assembly.

This often results from a micro‑leak at the seat, allowing high‑pressure gas to pass into the low‑pressure side.

When this happens, the outlet pressure gradually increases until the pressure relief valve activates.

Replacing this assembly solves the issue, and the operation only takes a few minutes. *See the “Downloads” tab for installation instructions.