Hello,
I recently noticed the pressure when I flush my grouphead goes up to about 4 bar. I cant remember specifically noting what it was when the machine was new but I'm wondering if this is a sign that I need to descale? I've been using RO water with a few ounces of hard tap water(350ppm) in each tank and have been running the machine daily for about a year now.

I was thinking to unscrew the top of the grouphead to check for any buildup but I don't have the correct wrenches at my disposal right now (about to move).

Any thoughts? Is 4 bar normal flow pressure with no portafilter clamped in?

Yes, it could be a sign that the gicleur is slightly clogged by scale. Given how easy it is to descale a single boiler like the Quickmill Alexia, I'd do it just in case.

PS: For those who may be wondering, it's normal for the brew pressure gauge to rise when the espresso machine is idle due to water expansion; the over-pressure valve allows water to escape to prevent excessive pressure.

Thanks for your response Dan. I've enjoyed watching your newbie videos.

After I descale, what would you expect the bar pressure to lower to when the pump is running without a portafilter?

I have a bottle of Saeco Decalcifier (citric acid, lactic acid, corrosion inhibitor). Should I run some of it through the grouphead or just through the steam wand as the product documentation states?

Because the brew pressure gauge tee is between the gicleur (orifice/jet) and grouphead, it will always register some backpressure, somewhere around 2-4 bar (guessing). Honestly, the only brew pressure reading that matters is during an extraction. As for descaling the gicleur, you'll need to run some through the grouphead.


Gicleur is shown in yellow near top; diagram courtesy of Lino Verna

If you're truly curious about whether scale is an issue, see Checking an E61 Espresso Machine for Scale for instructions.

Thanks Dan,
Always a wealth of knowledge!

I recently noticed the pressure when I flush my grouphead goes up to about 4 bar.

That is normal. It is due to the total restriction downstream of the boiler of which the 0.70 mm gicleur is the very major contributor.