Giampiero wrote:Yes as mentioned before, it sounds like cavitation.
Do you use any resin filter in the sucking pipe?

The only filter I'm aware of is the silicon one at the end of the tube that sits in the reservoir.

I believe the older Vetrano 2B's don't have any kind of filter along the water path.

The pump doesn't really care if there are kinks downstream, but it needs a free and clear path from the reservoir into the pump inlet with no restrictions whatsoever. Are you able to run a new line from the pump into a bucket or something like that to test and see if the noise is still there?

austinado16 wrote:Maybe if you took some detailed photos of the water line(s), someone here could give you some advice?

Since plastic has a memory, you could probably remove the waterline in question, and get it hot enough with a hair dryer, that you could reshape it, and then run cold water over it to make it cool down and retain the shape you created.

Here's some pics of the plastic water lines:




after routing one of the water lines under the pump/motor bracket, it's a little quieter but the buzz is still there.

I'm thinking I'll play around with that water line that's held on by a ziptie. I don't know why someone did that lol but that could very well be introducing air into the system.

Jake_G wrote:The pump doesn't really care if there are kinks downstream, but it needs a free and clear path from the reservoir into the pump inlet with no restrictions whatsoever. Are you able to run a new line from the pump into a bucket or something like that to test and see if the noise is still there?

Yeah, I'm going to play around with this later if I'm not able to remedy the issue by tightening up the water lines (specifically the ziptied line)

Alright I've now double checked all water pipes (they look fine) as well as tried running the machine using the plumb-in line. Still no luck

Does anyone know where I can buy a few of the plastic lines that come in/out of the pump? They would be very useful for when I test the pump on the bench.

Thanks!

borrik wrote:Is there check valve presented?

I'm not following, what do you mean?

He might be talking about a check valve at the bottom of the water tank, which allows the water tank to be lifted out of the machine with water still in it, without dumping water everywhere once it's been disconnected.

Does the plumbing fitting installed at the bottom of the machine it has a cap or you can see the thread?

I can see the thread.

My theory, that you can easily verify, is that the uncapped fitting does allow a bit of air to get sucked in the circuit despite there is a solenoid valve between.
Another theory is that maybe there is a partially clogged screen filter in the out line of the pump.
Another theory, based on the photos, it seems, just from my eyes, the pump is not a 50 lt/h, but with an higher flow rate, ( the pump neck is shorter in a 50lt/h) maybe an higher flow rate pump require an higher or inlet flow rate? i 'm asking because i'm not really sure.