Low pressure leak test

There's a hidden profile that can help you find subtle leaks.

High pressure leak tests don't always find all leaks:

Because a high pressure will cause the O-rings to deform and seal quite well. So a defective o-ring might only leak under low pressure

whereas a high pressure leak test will find defects in hard materials, such as tubing or the mixing manifolds.

There is a profile for doing this

Here is the description:

Put a blind (no hole) portafilter basket into your portafilter, and then run this profile to see if there are any water leaks in your machine. Once pressure is reached, water will be turned off and pressure held. After five minutes check with a flashlight for any water droplets inside the machine. You should not wait for the profile to stop. Start looking for leaks after 3 minutes and stop the profile once you feel assured there is no visible water leaking.

Here is a video of doing it:

a small amount of regular leakage is normal, as seals on valves are not perfect. This is normal, with occasional, regular ticks on the blue line:

whereas this much more frequent set of blue ticks that appears after some time, indicates a low pressure leak that takes a while to develop:

if you have this sort of leak, you can fix it by:

taking the chassis cover off

running this for several minutes

with a flashlight, look for a few drops of water.

ask Decent to send you replacement O rings. They're \very\* easy to replace (just need a pair of tweezers or needle nose pliers).

#troubleshooting #support #leaks

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mirjam created 2026/06/28.