Now that I've upped my technique and started getting better pulls my machine starts a new trick.

Pulls have been steady at 9 bar for a while. Shortly (but not immediately... a few days) after descaling and cleaning, my pulls went down to 8bar instead of 9.

The machine also typically has its normal "loudness", but now, you can watch the gauge go up to 8, but when it gets to 8 it gets very quiet.

Any ideas?

There are any number of reasons why it might have changed, but it's probably innocuous. Assuming that you prefer 9bar, adjust your pressurestat so that it's 9bar again and if the setting holds, I wouldn't worry about it.

So I'm not as worried about the change in pressure as I am the change+change in sound.

2-3 years of the machine, and its never quiet under full pressure.

But I'll yank the cover, set it to 9 again, and see what happens.

Your concern is understandable, but it's probably still innocuous. These are vague & benign symptoms, so if your machine otherwise operates properly it's little to worry about. It's probably just your heating element running on a lower duty cycle because you've removed some scale.

In any event, you haven't provided enough information to really say if anything is amiss. So unless the symptoms ring a bell with someone else, either further symptoms will arise making it more clear what is going on or (more likely) nothing further will change & nothing need be done. I suspect that if you are patient enough it will get noisier over time, as it builds scale & the heating element runs longer.

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The sound I speak of is from the pump, or so I assume.

I dialed up the pressure to 9, but its still "off" from the way the machine's always operated previously.

Normal: Flip up the lever, water flows, pump makes lots of noise (thank you very much vibe-technology), and it gets a tad louder while the pressure builds. And it stays at that volume level until you stop the pull.

Now: Flip up the lever, water flows, seems normal until pressure starts to build. Then, instead of louder it gets quieter, and while it now ramps up to 9, it then starts to "surge", and goes down to 8ish, and flounders between 8-9, but is very, very quiet.

I hope that's enough info / good enough description. Its definitely not working correctly...

You didn't mention that the noise you were referring to was probably the vibe pump (or describe it so that such could be inferred). It's hard to troubleshoot without information.

The change in sound is not necessarily meaningful. I've owned machines where normal vibe pump operation is quieter under load. If the pump maintains the correct pressure and your shot volume is reasonable, then it would seem to be a non-issue. If the pressure is erratic, more than the normal pressure flutter that vibe pumps produce or the volume is way off, it might be dislodged scale inside the pump. The pump can usually be disassembled to clean/service or replace. But it could just as easily be the OPV which may need cleaning or adjustment. HTH

In the interest of more disclosure (and my memory being jogged).. The sequence of events is this:

1) Descaled, with crappy instructions.
2) Descaled a 2nd time, with much better instructions.

After #2, machine works great. A week passes.

3) I get delivery of Cafiza powder, and clean the grouphead/OPV per the instructions.

These symptoms happened right after that... And now have been consistent. I've yet to get an up-to-pressure shot. The machine does its normal thing, ramps up the pressure, and then gets quiet, stops building around 8, and now fluctuates between 7-8.

With a blind basket it gets to 9, but very slowly, and doesn't for some reason seem to fluctuate as much.

Edit: With blind basket, just now, the 1st three times I flushed it it went to 7-8 bar. Then the last 3 slowly increased up to 9. But its still not remotely the right ramp up, and its way quieter than it ever has been.

Also, the machine is "normally noisy" until it gets up to about 6.5-7, where it then becomes quiet, even though it builds some more pressure.

There is an old expression, garbage in, garbage out. If you don't provide accurate information about what is going on, you aren't likely to get useful advice in return. If that sounds like I'm being a bit harsh it's because I am. By withholding a lot of relevant details you're not only getting less accurate advice but you're also making it hard and frustrating for anyone to try and help you. You're still pretty sparse with important details, such as how you went about the descaling and whether you've tried adjusting the pump pressure or not. But you've added enough details to paint a substantially picture than you started with.

You are now saying that your pressure dropped from 9bar to 8bar quite a bit after the descaling and proximate to doing a proper backwash. As it sounds like the machine wasn't back washed regularly before, there was probably a lot of gunk built up in the group. Some of that gunk or detergent may have washed through the OPV which controls the pump pressure. It's not clear if you have tried adjusting the pump pressure (OPV valve) or whether the change in behavior means that the OPV is now cleaner and working better. Or whether the OPV is malfunctioning because some crap from the group is now lodged in it.

Do a long series of detergent back washes, then try adjusting the OPV. If you can't get back to 9bar, I'd disassemble the OPV and clean it out. If that doesn't work, then do the same for the pump. An outside & I'd think unlikely cause would be that some gunk washed into the gauge path or that it is coincidentally sticking or failing. But my money is on the OPV being misadjusted and/or congested.

Apologies for the trinkling of info... It wasn't intentional. I just hadn't thought about the time-line of events.

I did another series of backflushes with the Cafiza and then cleaning flushes... Short version: Fixed.

Interestingly enough the 1st backflush was at a full 9 bar, and they all stayed there, and the machine worked like it normally does.

I think it was grumpy for a week.

This issue remains unresolved. I thought it was fixed, but it has come back. Some days the machine works normally, some days it does not.

When its not working correctly, if you insert a blind basket, it ramps up pressure to about 8, then gets really quiet, and the pressure drops to around 6.5-7, and just sits there.

Should I go about removing/trying to clean the OPV at this point?