5313220031 Genuine O-Ring Green Viton FKM 70 Shore, 9.25mm ID x 1.78mm Section, for De'Longhi Coffee Machines

This is De'Longhi O-ring 5313220031, a small green seal made from Viton (FKM) rubber with a 70 Shore hardness. It measures 9.25mm across the inside with a 1.78mm cross section. Viton is chosen for hot water and steam connections because it holds its shape under heat. As a genuine De'Longhi part, it's the seal to fit wherever your machine's parts list calls for 5313220031.

Leaks from coffee machine joints and O-rings

Inside an espresso or bean to cup machine, water travels under pressure through hoses, valves and connectors, and many of those joints rely on an O-ring rather than a clamp. After thousands of heat cycles and a build-up of scale, O-rings flatten, harden or get nicked, and the joint starts to weep. You might notice water pooling under the machine, a full drip tray when it hasn't been used, hissing from inside, or weak pressure at the spout. A new O-ring often cures what looks like a far bigger fault.

Part details

• Genuine De'Longhi part 5313220031
• Viton (FKM) rubber, 70 Shore
• Green
• 9.25mm inside diameter
• 1.78mm cross section

Fitting a new O-ring

Unplug the machine and let it cool before opening it up. Remove the old O-ring with a plastic pick so the groove isn't scratched, then wipe away scale and old grease. A light smear of food safe silicone grease helps the new ring seat without twisting. Roll it into the groove evenly, refit the connection and run water through to check for drips.

Questions about this part

How do I know this is the right O-ring size?

Measure the old ring's inside diameter and thickness, or better still, check the parts list for your machine for 5313220031. O-rings that look alike can differ by fractions of a millimetre, and the wrong one can leak under pressure.