The S1 Cafe - Helping Your Espresso Dreams Become Reality

Hi, I have an S1 and I’ve recently noticed that randomly it takes maybe 8 seconds to get pressure at the group head. The pressure / pump works fine 90% of the time. I’ve checked the check valve and water tank and all seems ok. I can hear the pump run but the pressure to the group head is delayed and this ruins the shot.

I show the water flow inside the Mini in the diagram below. I labelled a part "expansion valve" in this diagram but that is because that is what the same part is used for in the plumbed-in version. However, in the Mini, it is used to adjust group pressure. You're not the first one to post with this problem. I normally suspect this part since it is just a rubber piece on the end of a spring that blocks a hole which lets water through. However, to a man, all the others have found that the pump itself is the culprit.

You may still want to dissasemble this valve to check for a partial clog since doing that is free. However, the pumps are not too expensive, if it should come to that.

Hi, thanks for the response. Are you referring to the over pressure valve that sits just below the vibe pump on the diagram?
Many Thanks
Glen

yes

Were you able to fit the problem?

I’m planning to start the repair next week. I’ll keep you posted