Why is my old o-ring larger than the new replacement one you supplied me, can I have my money back…please read below?

I sometimes get customers writing to me and telling me I have supplied the wrong size o-ring, especially on the infuser/brew unit seal. The old o-ring appears larger than the new one. This is especially common with my Saeco customers. Most Saeco coffee machines have not been serviced for years, so the ring on the brew unit is warped and stretched. See the photo below, the older oring clearly looks bigger.

saeco brew unit o-rings

I have conducted research into orings and they are designed to be compressed but different application and fluids will result in swelling and stretching. Yes they will swell, in fact if you google it you will read that in some applications a 25% change in volume can be expected. It all depends on the application, the lubrication, the cavity in which they are housed etc. You can imagine the life the o-ring in the brew unit gets. It does not stay lubricated and gets covered in grit, it also gets pulling action stretching it each time it moves up and down the brew unit shaft.

There are many articles online about the factors effecting silicon o-rings and careful engineering is required to ensure they work and last. The ones in your coffee machine brew unit are not meant to last forever and are probably not engineered as well as the challenger space shuttle was, yet they failed as well. Brew Unit o-rings need replacing every 5k cups at least. They do swell and they do stretch, especially if its been in there 10 years.

I also need to point out that some brew units warp over time as well. This is especially true of Delonghi. Once the old o-rings are replaced, we sometimes get leakage until the new ones swell a little. I believe its caused by the inner chamber of the new unit becoming warped. Its only plastic. DeLonghi Brew units are not expensive so best to replace it if this occurs.

To ensure you have not been sent the incorrect oring size I will be posting right here the manufacturers specifications for o-ring size. As soon as I have them they will be posted here. All official, then you can measure for yourself.

Coming?

 

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