Replacing the Safety Valve


Replacing the valve is a simple process. With the right tools it shouldn’t take more than a minute.

But first, an important warning:

The Mk. 2 safety valve has a manual release button, this button should only be touched once the machine is completely cool.

During normal operation the boiler and the safety valve will get burning hot. Additionally, if you press the button while the boiler is hot, scalding steam will be released from the valve, and could burn you.
Either wait for the machine to completely cool down, or cool it under the cold tap, before you use the pressure release button.

After brewing an espresso, and once the machine is completely cool – you should press the button on the safety valve to equalise the pressure in the lower boiler (you’ll hear a slight hiss). This will make unscrewing the boiler much easier.


Tools and parts required


  1. Remove the existing valve by unscrewing the whole valve. You may be able to do this with your fingers. If not, use a 13mm spanner (wrench), to loosen it. You want to place your spanner around the nut – that’s the part of the valve that has flat sides. In the image above it’s directly above the gold coloured safety ring, it’s on the outside of the boiler.
  2. Screw the new valve in to the hole left by the old one. Screw it in hand tight, then use a 13 mm spanner to tighten so there is “metal on metal” contact between the boiler and the valve.

    You won’t need to tighten it very hard, the thing to feel for is a sudden increase in resistance when screwing it in (that’s when you get metal metal contact).

That’s it! If you have any questions, please either add a comment below, or contact support.


6 replies on “Replacing the Safety Valve

  • Joshua Brown

    You mention running it under a cool tap. Is there any concern with thermal stresses when doing that (or putting it in a cold water basin when camping)? I’d hate to ruin the material integrity of the boiler.

    • Ben @ 9Barista

      Hi Joshua – no, there are no concerns with that – the brass is thick and an inherently strong shape, so it’s absolutely fine to run under the cold tap, even when very hot right after brewing.


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