Brand new Unit - low pressure from group head

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jfmasse

Brand new Unit - low pressure from group head

Post by jfmasse »

https://drive.google.com/file/d/1tIY63L ... sp=sharing

Hi everyone,

Yesterday I replaced my old QuickMill Vetrano Single boiler with a S1 Vivaldi II. I have a flow problem. I don't have the Dual Manometer so I don't know the real pressure. When I start the pump, the flow seem ok but a couple of seconds later it drops. The video clearly shows it. The shop in Montreal told me they can change the unit but but I won't be able to got this week. Anyone have clues for what could be the problem?

Thanks
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chas
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Re: Brand new Unit - low pressure from group head

Post by chas »

There are a few key possibilities:

1) If the expansion valve adjustment is wrong, water may be dumping through a pipe and directly into the drip tray rather than flowing through the group head. You would see this water flowing into the rear right corner of the drip tray while pulling a shot.

2) It is also possible (this happens more often than it should) that a metal burr from the manufacturing process got into the water line and is partially clogging either the flowmeter or the 3-way valve at the group head. In either of these cases there is apparently still enough water getting through to NOT trigger the flowmeter alarm.This is seen as either three green or three yellow blinking lights depending on which button you pressed initially. I assume is this was happening you would have mentioned it.
Chas
LM GS/3 & LaSpaziale Dream v 1.25 (US 120V)
Mazzer Kony E, Customized Rocky
Hottop P/B
jfmasse

Re: Brand new Unit - low pressure from group head

Post by jfmasse »

Hi Chas,

There is no water flowing into the rear right corner of the drip tray while pulling a shot. And there is also no three green or three yellow blinking lights.

Thanks.
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chas
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Joined: Wed Jun 02, 2004 11:52 pm
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Re: Brand new Unit - low pressure from group head

Post by chas »

The flowmeter has filter screens just before its input and at its output. It might be worth a check of both screens for a partial blockage. See the diagram below for location of the two screens (part # 275). The flowmeter is right behind the front chrome panel with the pressure gauge sticking through it. You can unscrew the input and output water connections to check these filters without removing the flowmeter.

If you really have a mind to tear into your machine to check this out, you can likely find the problem and fix it yourself. However, given that it's a brand new machine and the vendor is willing to send you a replacement, I wouldn't blame you for doing that!
2018-02-19_10-33-35.jpg
2018-02-19_10-33-35.jpg (13.57 KiB) Viewed 35854 times
Chas
LM GS/3 & LaSpaziale Dream v 1.25 (US 120V)
Mazzer Kony E, Customized Rocky
Hottop P/B
jfmasse

Re: Brand new Unit - low pressure from group head

Post by jfmasse »

@chas : You're right. I went back and exchanged. The new unit is perfect. :)
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chas
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Joined: Wed Jun 02, 2004 11:52 pm
Location: Central Maryland
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Re: Brand new Unit - low pressure from group head

Post by chas »

Glad to hear it. You will want to buy or build a portafilter pressure gauge at your earliest convenience. You can buy a pre-built one for about $100 USD but much of that price is for the portafilter itself. It is cheaper since the S1 comes with two portafilters to just buy a gauge that screws onto the bottom of one of the portafilters you already have.

This one is made to screw right onto the PF: https://www.espressoparts.com/portafilt ... -gauge-kit

The key reason you need one sooner than later is due to the fact that the rotary pump adds a pressure boost to the incoming water pressure. Assuming it was adjusted to 9bar by your vendor, if their water pressure was 60psi and your house water pressure is 45psi, then you are only getting 8bar of pressure at your PF. In other words any difference in water pressure from where the machine was adjusted versus your house water pressure will be reflected as an error in your machine pressure.

The machines hold their settings really well. So once it's adjusted for your house pressure you don't need to check it again unless your house pressure changes.
Chas
LM GS/3 & LaSpaziale Dream v 1.25 (US 120V)
Mazzer Kony E, Customized Rocky
Hottop P/B
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