Preinfusion spring & omitting it

hedonist222

I forgot to install the stiffer flow control device spring on my new to me r58.

After installing it, I noticed that I had to grind much coarser for the same beans I’d calibrated.

I mark grind settings on each bag of bean.

I dial a bean to start dripping between 6 and 9 seconds.

With the differ spring, first drip started at 12 to 15 seconds.

What I deduce is that the softer stock spring was allowing for some preinfusion.

How does one trigger preinfusion on a stock e61?

How does it work?

How does a stiffer spring eliminate it?

Thanks

DavecUK

hedonist222 How does one trigger preinfusion on a stock e61?

How does it work?

How does a stiffer spring eliminate it?

It’s automatic, the preinfusion chamber opens at 4 bars, for a fraction of a second or so…which does…nuthin really with a rotary.

The stiffer spring won’t let it open at 9 or 10 bars, so the little chamber doesn’t fill.

hedonist222

So why eliminate it with a flow control device?

DavecUK

hedonist222 So why eliminate it with a flow control device?

So you don’t get any disturbance, especially if you are using a fairly low flow gradual ramp in pressure, and dip that in chocolate (as K bacon would say in his advert) if using a vibe pump.