Whistling or high-pitched noise

Post by **bbqnut** » Fri Nov 02, 2007 12:59 am

Now that the new pump is in, and think the expansion valve might not be calibrated perfectly, I am getting this noise. I can only describe it is a whistling noise, or maybe a high pitched whine.

It happens about every 2-5 minutes, and is very, very brief (maybe 1-2 seconds), and is very subtle in terms of location. It seems to correlate with the either the steam or group boiler having to reheat (blinking light). Even standing over the open machine, I am not 100% sure it is even coming from the espresso machine, but

Is this a known issue?

Could this in any way be related to the expansion valve being too tight? Too loose?

Any other ideas?

Thanks

Post by **Niko** » Fri Nov 02, 2007 2:06 am

Chris,
is it similar to this thread? viewtopic.php?t=454&highlight=whistling+noise

Post by **bbqnut** » Fri Nov 02, 2007 11:21 am

Looks like exactly the problem.

Somehow, after all that calibration, the expansion valve started dripping even when the machine was at idle. So every 12 hours, I would tighten about half turn, until it stopped (I know I need to recalibrate).

Maybe for some reason it is now too tight.

Thanks for that thread, I think that is it.

I guess here is another question: Is there any harm in the expansion valve dripping at too "low" of a pressure? I have a plumbed in drip tray, so that is not the concern. Just wondered if it affects the group pressure, and ultimately the shot?

Post by **Niko** » Fri Nov 02, 2007 12:03 pm

My other S1 (Viv I) had a similar problem with the expansion valve, it kept dripping and dripping for days. I had to empty the tray every 6 hours even though the machine was off. It turned out to be something stuck which luckily, Cafiza was able to flush out (chunks of old, oily coffee). We know this probably isn't the case with yours, so maybe run a few Cafiza shots through with a white paper towel in the drip tray (below the expansion valve exit tube) to see if anything comes out. I would say it's more the fact that you changed the pump and it still needs a tweak or two, sometimes the gauges aren't reading exactly what their supposed to read which is another reason I'm hoping that Mr. Gregory Scace would hurry up and build that Scace2 device for me. That manometer he uses is supposed to be top notch quality AND the fact that the pressure reading is what's happening to the coffee puck itself, not in the plumbing before the action really hits the grinds.
Another thing, what if...
there's another piece of brass shaving stuck in the valve (yet again) due to moving the machine around around all over the place while replacing pump?

Man, you must have quite the forearms by now!

Post by **bbqnut** » Fri Nov 02, 2007 12:06 pm

Niko wrote: Another thing, what if...
there's another piece of brass shaving stuck in the valve (yet again) due to moving the machine around around all over the place while replacing pump?

Man, you must have quite the forearms by now!

Yes, brass shavings - they have become my bane of my existence.

I think I will just loosen it again little by little, and see if it helps.