S1 Pre Infusion issues

[AYarter]

Hello! I have a plumbed in S1 and am having an issue with the pre-infusion. When I start the machine in the morning, or after any period of inactivity (approx 1 hour) when I hit the 'brew' button I get no water for three of my four seconds of programmed pre-infusion. Any shots after that are fine, unless I let the machine idle awhile. This is usually remedied by running a heating flush anyways, but would like to get to the root cause.

Some background, there is a new filter setup behind it, a softener and carbon filter. Pressure at the grouphead is as expected (approx 2 and a half bars) and flows fine once the brew is started. This behavior seems to have started after installation of the new filters, but I can't be sure. I can't automatically fault them because the line pressure is fine when it is off the machine and according to the gauges.

Any thoughts on how to start troubleshooting? I've looked into past posts and nothing.

Adam

[chas]

Quick Question: When you saw nothing coming out during pre-infusion, was the with an empty PF or a full one?

[AYarter]

Hi! It was empty, and the issue shows with no portafilter in.

[chas]

The boiler initially fills and remains full, when the pump is not running via the normal water line pressure. It seems that this is not happening for you and, instead the boiler is partially emptying. I am at a loss as to what might make this happen.

Is any water dripping into your drip tray from either the expansion valve or the 3-way drain pipe during an extended interval when the pump is not running? BTW: There should be no dripping from the 3-way pipe during this time but a few drops coming from the expansion valve is normal every time the group boiler's heater element turns on.

[AYarter]

Hi Chas:

Sorry for the delay in my response. I broke my foot in the last few weeks and haven't made it back here.

Yes, there is, and it's more than a few drops. It's a pretty significant amount. I'm going to replace the seat in the OPV and hope. Any thoughts?

[chas]

It sounds like your previous repairs did NOT require you to either loosen or remove that expansion valve so it is probably the rubber seal. It may have just chosen that moment to crack. That valve fitting should be tightened via screwing it in until the valve just starts to drip when the group boiler pressure hits 12bar. If the rubber fitting at the end of the spring is either cracked or off-center it will not seal correctly even if the valve is screwed all the way in.

The proper adjustment method is covered on pages 17 and 18 in this manual: http://s1cafe.com/s1v1/S1Pix/S1OwnersManual.pdf.

Unfortunately, if you truly have an S1 with only a steam boiler pressure gauge on the front panel, you will need to make or buy yourself a group pressure gauge before an accurate adjustment is possible. If this is the case, the pressure gauge will cost more than the rubber fitting since those are $4.95. Of course, shipping may not be included unless can have other items you need to bring up to total price.

[AYarter]

Chas:

This makes a ton of sense. I've ordered the parts and will do this when back in town.

Thanks so much!