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Adjusting vibe pump pressure on HX machines
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HB
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Joined: 3 Apr 2003
Posts: 2,913
Location: Cary, NC
Posted Tue May 4, 2004, 4:05am
Subject: Re: Adjusting vibe pump pressure on HX machines
 

strugs Said:

can I just add a gauge with a "T" fitting immediately after the pump?

Posted May 3, 2004 link

That's exactly what I did.  As it turns out, Valentina uses compression fittings that also work with John Guest 1/4" 230 PSI tubing (so does Expobar, according to Keith Monaghan (MOSFET)), so it was a quick job.  I used a cheap gauge from Ace Hareware and a snubber.

-- Dan

HB: val-pump-gauge.jpg
(Click for larger image)

 
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MOSFET
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MOSFET
Joined: 31 Dec 2003
Posts: 376
Location: Long Island, NY
Expertise: I like coffee

Espresso: Linea
Grinder: Mazzer Mini
Vac Pot: Hoover
Drip: Post-nasal
Roaster: Perdue Oven-Stuffer
Posted Tue May 4, 2004, 5:09am
Subject: Re: Adjusting vibe pump pressure on HX machines
 

but do not want to make some sort of frankenstein portafilter

...

That actually sounds neat. I'd love to have a frankenstein portafilter to compare readings with the other gauge. Keeping in mind taste is the ultimate gauge, it would still be interesting to see how much drop there is between the teed gauge pressure and the actual coffee pressure. Probably very little, though.

The only addition I'd make to the tee gauge procedure is be sure to retain the original compression fittings that connect to your pump and to your boiler inlet. Reuse them, but with John Guest tubing replacing what it came with. For the actual tee section you can use American fittings with the same tubing. If you ever want to replace the original fittings, they are deceivingly close to National Pipe Thread, but are in fact British Pipe Parallel. The NPT has 18 threads per inch and the BPP has 19. It feels like it fits but will only go in a couple threads. I ordered the correct fittings and can dig up the info if anyone ever needs. But for the gauge job you don't need to if you reuse the original fittings and use an NPT tee/fittings.

Keith
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MOSFET
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MOSFET
Joined: 31 Dec 2003
Posts: 376
Location: Long Island, NY
Expertise: I like coffee

Espresso: Linea
Grinder: Mazzer Mini
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Drip: Post-nasal
Roaster: Perdue Oven-Stuffer
Posted Tue May 4, 2004, 5:19am
Subject: Re: Adjusting vibe pump pressure on HX machines
 

For reference - these should have more gauge details: (The first shows the actual gauge I used and has worked great for months now)

Expobar with Gauge
The Six Million Dollar Expobar

Keith
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strugs
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strugs
Joined: 21 Jul 2003
Posts: 658
Location: Vancouver, Canada
Expertise: I live coffee

Espresso: Vincent Wega (Wega Lyra)
Grinder: Jules (Mazzer Mini)
Vac Pot: Hario TCA-5
Drip: Tray
Roaster: 49th and/or Intelly
Posted Sat Jun 26, 2004, 6:06pm
Subject: Re: Adjusting vibe pump pressure on HX machines
 

jim_schulman Said:

you can approximately set these things without a pressure guage. Vibe pumps drain 2 to 2.5 ounces of water in 25 seconds when they are at 8.5 to 9.5 bar. So put in a blind filter, use a measuring cup to catch the run off back to the tank, and adjust it to get that flow rate (wait for the pressure to max before measuring, you'll hear this in the pump going quiet as the flow stops, it'll take up to 10 seconds for preinfusing ones).

Posted April 16, 2004 link

OK - my apologies to Jim, as he provides more helpful advice here than most other members put together.  However, I just wanted to point out that what may work on another machine (or work in theory) may not apply in all cases.  

Shortly after receiving my Wega Lyra, I fiddled with the pressure releif valve.  Don't aks me why - the Lyra does not come equipped with a pump pressure gauge like the Tea or Rituale, so I had no way of knowing what my pressure was set to before or after playing with the set-screw on my machine.  I do a quick search, and find this thread.  Then I head off to make the adjustment like Jim recommends.  I set it so that a little over 2 ounces of run-off came out of the PRV bypass line and thought I was golden.  The only thing a little troubling was that in order to achieve this amount, I had to adjust the set-screw all the way counter clockwise.  I knew that this was not the way it was set by my vendor, but I chalked it up to an improper setting from the factory.  Since making this adjustment, my shots seemed to always be too bitter or too sour - I had a hard time acheiving a happy medium.  I wondered if the pressure was set wrong, but since I did not have the built in gauge I had no way of knowing.  So - off I go to talk to my pals at Espressoparts, and order the portafilter pressure gauge.  After I hook up the gauge, I quickly determine that the pressure was set wayyyyyy too high.  It was at almost 15 bar!  I adjust it down to a more civilized 9 bar, and lo and behold, my shots are now much better.  I am back to enjoying straight espresso.

As I pointed out above, I hate to disagree with Jim of all people, but for those that are trying to set your pump pressure, I strongly urge you to invest in a gauge rather than rely on runoff volume, as that method turned out to be quite inaccurate (at least on my machine).  The real strange thing about my current setting at 9 bar (according to the PF gauge) is that I actually get zero runoff when running the pump with a blind filter.  No idea why, as this seems counter-intuitive to the way an overpressure valve should work....

 
- Sean
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HB
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Joined: 3 Apr 2003
Posts: 2,913
Location: Cary, NC
Posted Sat Jun 26, 2004, 7:02pm
Subject: Re: Adjusting vibe pump pressure on HX machines
 

strugs Said:

...for those that are trying to set your pump pressure, I strongly urge you to invest in a gauge rather than rely on runoff volume, as that method turned out to be quite inaccurate (at least on my machine).

Posted June 26, 2004 link

I agree that without the specifications of your specific pump, runoff measurement may be hit and miss. The Ulka website has the performance curves for all their products (link).  There you'll see some variance, as one would expect, so again this technique is only an estimate.  The table below shows the max values.  Most Isomacs have an EX5, if I remember right.  Mine has an EP5.  Whaaaa-t, plastic!?!  Indeed, I was not pleased to see that -- I believe this is what 1st-line chose when converting it from the Fluid-o-Tech.  :-(

The real strange thing about my current setting at 9 bar (according to the PF gauge) is that I actually get zero runoff when running the pump with a blind filter.  No idea why, as this seems counter-intuitive to the way an overpressure valve should work....

Strange is an understatement.  Fifteen bar with two ounces of runoff, none with nine bar.  Does not compute.

-- Dan

HB: ulka-type-e.jpg
(Click for larger image)

 
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syd
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syd
Joined: 30 Jun 2004
Posts: 436
Location: Melbourne
Expertise: I like coffee

Espresso: Sunbeam EM6910
Grinder: Mazzer Mini-E
Roaster: Many
Posted Sat Nov 20, 2004, 6:15pm
Subject: Re: Adjusting vibe pump pressure on HX machines
 

strugs Said:

Shortly after receiving my Wega Lyra, I fiddled with the pressure releif valve...  After I hook up the gauge, I quickly determine that the pressure was set wayyyyyy too high.  It was at almost 15 bar!

Posted June 26, 2004 link

I too have just done the same on my Lyra with Mininova's pressure gauge. "Re: Attn: All Wega Mininova owners, check your pressure!".

Mine was set way high as well. I wonder why the factory does this?
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strugs
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strugs
Joined: 21 Jul 2003
Posts: 658
Location: Vancouver, Canada
Expertise: I live coffee

Espresso: Vincent Wega (Wega Lyra)
Grinder: Jules (Mazzer Mini)
Vac Pot: Hario TCA-5
Drip: Tray
Roaster: 49th and/or Intelly
Posted Sun Nov 21, 2004, 12:08am
Subject: Re: Adjusting vibe pump pressure on HX machines
 

HB Said:

Strange is an understatement.  Fifteen bar with two ounces of runoff, none with nine bar.  Does not compute.

-- Dan

Posted June 26, 2004 link

A few months ago I found out why this seemingly impossible situation can happen.  It will occur on all WEGA's (at least all Lyra/Mininova models).  The reason is that the OPV valve's runoff (that bleeds excess water away from the brew line) is routed back to the pump inlet.  There is also another OPV on the WEGA machines near the bottom of the boiler.  I have received conflicting info on what purpose it serves, but it is in-line with water inlet pipe that routes water into the HX loop.  I have a theory that this has something to do with the fact that WEGA's have a second HX loop that heats the water for the hot water tap.  Most all other machines in the pro-sumer class draw hot water directly from the boiler.

Another "crazy WWDP theory" tidbit for all Lyra owners - make sure you flush your hot water tap prior to flushing the main HX line.  Someone (Terry Z?) can correct me if I am wrong, but the two HX lines seem to be connected on the inlet end (where the 2nd mysterious OPV valve is located).  When you perform the cooling flush of the brew HX system, there is still a lot of superheated H2O in the hot water spout system.  Just when you think you have flushed all the hot water out and have reached your target brew temp, the overheated water from the water spout HX system gets pulsed into the brew HX.  The reasoning behind my theory came to me after wondering why my Americanos are never bitter, but my espressos have always had a slight to moderate bitter taste even after marathon group flushing sessions (11 oz).  Of course what do I do before making an Americano?  Fill my mug with hot water....that's what.  I tested my theory earlier today and it seems to be sound.  I made an espresso after doing a hot water flush followed by a group head flush (5 oz), and the shot only had a hint of bitterness.  I am in the midst of doing my first descaling operation with the WEGA so I was unable to do any more testing today.  I will see if this theory holds water tomorrow and try to report my findings.

Speaking of the descaling operations - what a major pain in the a** - has anyone found an easy way to get descaling solution into a sealed boiler that is plumbed in?  I probably did it the hard way.  I removed the carbon water filters from their housings (I have one of those 10" cylinder filter systems with a double housing) and filled the housings with descaling solution than plugged them back in.  I think next time I will hook up an external bottle containing the solution and hook it into the pump inlet line.  Anyways - what I did seems to have worked - I saw lots of green goopy water coming out of the brew head after just letting the machine warm up for a few minutes.  I just unplugged the machine and will let it sit overnight and let the citric acid solutin do its thing.

 
- Sean
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syd
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syd
Joined: 30 Jun 2004
Posts: 436
Location: Melbourne
Expertise: I like coffee

Espresso: Sunbeam EM6910
Grinder: Mazzer Mini-E
Roaster: Many
Posted Sun Nov 21, 2004, 12:54am
Subject: Re: Adjusting vibe pump pressure on HX machines
 

strugs Said:

There is also another OPV on the WEGA machines near the bottom of the boiler.  I have received conflicting info on what purpose it serves, but it is in-line with water inlet pipe that routes water into the HX loop.

Posted November 21, 2004 link

Sean, have you got any pics of these? I've been tweaking two valves, the second of which I understand as the safety valve. I got these from the parts list pdf. I hope I'm adjusting the right ones!
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strugs
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strugs
Joined: 21 Jul 2003
Posts: 658
Location: Vancouver, Canada
Expertise: I live coffee

Espresso: Vincent Wega (Wega Lyra)
Grinder: Jules (Mazzer Mini)
Vac Pot: Hario TCA-5
Drip: Tray
Roaster: 49th and/or Intelly
Posted Sun Nov 21, 2004, 9:58am
Subject: Re: Adjusting vibe pump pressure on HX machines
 

I do have pics somewhere, but I just reformatted my computer so I will have to dig through my picture archives.  In the meantime, do you have the prts list pdf?  I would like to see that....

 
- Sean
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syd
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syd
Joined: 30 Jun 2004
Posts: 436
Location: Melbourne
Expertise: I like coffee

Espresso: Sunbeam EM6910
Grinder: Mazzer Mini-E
Roaster: Many
Posted Sun Nov 21, 2004, 1:09pm
Subject: Re: Adjusting vibe pump pressure on HX machines
 

It's for the MiniNova, not the Lyra. Do you still want it?
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