Journey of Repairing Motor on Quick Mill Vetrano 2B - Page 5

#41: Post by **borrik** » February 8th, 2023, 3:45 am

glinskonian wrote:I'm not following, what do you mean?

It should be valve like this:
https://clivecoffee.zendesk.com/hc/en-u ... heck-Valve

#42: Post by **Giampiero** » February 8th, 2023, 4:40 am

Giampiero wrote: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 in 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.

#43: Post by **Giampiero** » February 8th, 2023, 4:42 am

Sorry i wanted to modify the post since i previously wrote to check the "out line" of the pump

February 8th, 2023, 10:17 am

Giampiero wrote: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.

I don't think the uncapped fitting is the issue as it still makes the buzzing sound even when I run the machine plumbed in (unless I'm missing something).

As far as I know, there is no screen filter on this older Vetrano except for the screen on the end of the tank water line as well as the plumbed in fitting on the bottom of the machine (which look ok).

Hmmm you know what, the new pump I had installed definitely has different dimensions than the stock one. I noticed that it's much harder now to get the water lines attached to the pump because of the different orientation/length, so I'm going to look into this more.

The stock pump for this machine is a PA101 fluid-o-tech which operates at ~38 GPH, so I'll know the new pump is incompatible if it has a flow rate that's something much higher than this.

Thanks.

#45: Post by **Jake_G** » February 8th, 2023, 5:40 pm

Wait, you replaced the pump?

February 8th, 2023, 8:02 pm

Ok so after further tinkering, I think I found the issue: one of the Teflon male connectors on the pump has a damaged outlet (where the end of the valve connects to the Teflon water line). It was severely bent, and I think this is what's causing the cavitation.

I tried to widen the hole back to what it should be, but I can't get it close to the original diameter.

I've ordered a replacement from Chris Coffee and will update everyone on whether this solves my pesky noisy machine.

February 15th, 2023, 8:31 pm

Update: I replaced the Teflon male connectors on the pump which didn't seem to help.

I also ran water lines directly to the inlet of the pump to eliminate any possibilities of a clog or something within the machine. That also didn't change the sound.

I even went as far as going back to the espresso shop and swapped out the pump they had replaced for a different one. I was pretty sure that the pump they had given me was a dud, but low and behold when I put the new one on today, I'm still getting the same noise!

I'm extremely frustrated at this point, kind of running out of ideas as to what could be causing this and possible solutions...

If anyone has insight as to what else I could check, that would be appreciated.

#48: Post by **borrik** » February 16th, 2023, 1:48 am

You could try to listen individual parts via some wood stick and locate exact source of the noise. Did you tried to play with pump's relief valve?

#49: Post by **Giampiero** » February 16th, 2023, 2:36 am

At this point i would bypass all the solenoids and check valve assembly, just connect the silicone inlet pipe directly to the pump, at least you can verify if the issue is in the section just bypassed.

#50: Post by **cyclery** » February 18th, 2023, 1:25 pm

Something inexpensive to try is replacing the rubber insulating bumpers. I have an even older QM Vetrano. One day last year, the motor started to make a buzzing noise and vibration similar to what you're hearing. I took out the motor and ran it on the counter, where it ran quietly. I checked the pump, which rotated smoothly. When I reassembled everything, the machine still made the buzzing noise. The original bumpers felt and looked fine, but they had to be the problem. My old Vetrano's bumpers are under the motor rather than suspending the motor, but the same principles apply.

I found suitable bumpers online for pretty cheap, I think under $10 for 8. After installing them, the machine went happily back to nearly silent operation. It might be worth a try to isolate at least one variable.