SSIA.

Started a few weeks ago, but only happened very infrequently. I chalked it up to a choked machine and assumed I was somehow losing pressure through the solenoid valve. In hindsight, I'm realizing that isn't possible anyways (or indicative of a separate problem). Fast forward to this morning.

Every shot I pulled followed this pattern:

1) Pressure builds to 9-10 bars.
2) Pulls for a second or two.
3) Usually loud vibe pump goes MUCH quieter and pressure gauge begins to fall.
4) Shot continues to pull as pressure falls to about 4 bars.

The most indicative and readily noticeable symptom for me, other than the loss in pressure, is the sounds of the pump. It goes super quiet, almost like a rotary. A low a hum. Shots pulled with this problem are super sour and acidic.

I'm going to try and pull a few in the AM and see what happens, then I plan to open up the machine, which I bought used and haven't really done yet. I'm going to started looking for loose gaskets/hoses, as well as try to take a look at the pump. I don't have any experience with the inner-workings of the MV 2 yet though. So other than unplugging the machine so I don't burn my face off, what should I be looking for? What could my problems be? Any info is appreciated so I can get right to work tomorrow.

JerDGold wrote: 1) Pressure builds to 9-10 bars.
2) Pulls for a second or two.
3) Usually loud vibe pump goes MUCH quieter and pressure gauge begins to fall.
4) Shot continues to pull as pressure falls to about 4 bars.

What you describe is a failing Ulka vibratory pump. That is the first place I would look.

Agreed. I had pretty much the same problem a year ago and a quick replacement of the pump solved it.

So I pulled a few satisfactory shots today with now pump failure. Is this indicative of anything? Could something be causing an otherwise working pump to fail sometimes?

The symptoms are similar to what occasionally happens when the steam boiler auto fill comes in coincident with pulling a shot. Essentially the pump is discharging through both flowpaths at the same time and this drops the pressure. Do you make milk based drinks? Try steaming after the shot instead of during or before.