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Date: 23 Nov 2006 10:58:47
From:
Subject: hooked up a new pump to my silvia, something's wrong
I bought a used fluid-o-tech pump off of ebay, and I have hooked it up
to my Silvia.

I did this priily because I wanted to have better control over the
brew pressure, and many iterations of taking apart Sylvia's
over-pressure valve and testing seemed like a pain.

Anyway, the setup is all hooked up and 'works'. The problem is that
when I start a shot, I get a quick 'splash' of water/coffee coming out
of the portafilter, half an ounce or so, before the stream settles down
to a normal rate for the rest of the shot. It tastes awful.

I have a pressure gauge right after the pump (before the line goes into
silvia), and the pressure looks ok, but the problem remains... I have
adjusted the pressure as low as 7 bar, as high as 11, no real
difference.

Anyone have any ideas?





 
Date: 28 Nov 2006 12:19:27
From: daveb
Subject: up a new pump
hmmm, all that and

THEY WORK WELL!

Andy Schecter wrote:

>
> It's cheap and ubiquitous. Isn't that reason enough to replace it? :-)
>
> But seriously, it's annoyingly noisy, too.
>
> --
>
>
> -Andy S.
>



 
Date: 27 Nov 2006 22:47:20
From:
Subject: Re: hooked up a new pump to my silvia
Hi all,

Thanks for the info. I figured it was the flow rate, since that was
the problem, rather than boiler temp, since it's already PIDded, and
then I did the test.

I was 'pleased' to see that 10s without the portafilter went over
500ml, so that's definitely the problem.

Reading online, I think that the Silvia does not have a swappable
gicleur... From a post on home-barista.com forums:

http://www.home-barista.com/forums/viewtopic.php?p=12249#12249
========
The "orifice" in Silvia is located in the small 3-way valve adaptor
that bolts to the grouphead. The reason I call it an orifice is that it
receives the water from the, IIRC, 6.0-6.5 mm ID standpipe inside the
boiler. Water from the "orifice" fills the small volume associated with
this adaptor and 3-way valve, makes an abrupt U-turn, and heads towards
the grouphead passageways.

IIRC, the size of this opening is about 1.0 mm (or less) and forms the
seat for the 3-way valve in the de-energized position.
========

So, I figure I'll just get a needle valve.

My current setup is: 3/8" intake to pump, 3/8" output to a T
connector, one output of the T has my (cheapo home depot) pressure
gauge, the other piece goes to the 3/8"- >1/8" reducer, and the line
from that goes into silvia.

Does it matter where I put the needle valve? Should I try to put it
'close' to the group?
I don't think I understand how water pressure works, it seems to me
that after passing through a tiny orifice like this, the pressure
should be lower on the other side.



  
Date: 28 Nov 2006 10:27:57
From: Andy Schecter
Subject: Re: hooked up a new pump to my silvia
dleary@gmail.com wrote:
> My current setup is: 3/8" intake to pump, 3/8" output to a T
> connector, one output of the T has my (cheapo home depot) pressure
> gauge, the other piece goes to the 3/8"->1/8" reducer, and the line
> from that goes into silvia.
>
> Does it matter where I put the needle valve? Should I try to put it
> 'close' to the group?

It matters. You should put it after the pump, before the pressure gauge.

> it seems to me
> that after passing through a tiny orifice like this, the pressure
> should be lower on the other side.

Yes, there will be a pressure drop going through the needle valve that will be
proportional to flow rate. Once the flow rate settles down (after the first
few secs of the extraction), the pressure drop will be small.

You locate the gauge after the valve so that your gauge readings are closer to
what the puck actually sees.

One valve that will work is a McMaster.com 4995K15, although you will better
adjustability if you bush down to 1/4" and use the 4995K13.

--


-Andy S.

http://www.flickr.com/photos/andy_s/sets/


  
Date: 28 Nov 2006 09:07:18
From: Coffee for Connoisseurs
Subject: Re: hooked up a new pump to my silvia
>I was 'pleased' to see that 10s without the portafilter went over
>500ml, so that's definitely the problem.

+5 x design specs. You're starting to get into "why did I do this"
territory. It would be cheaper to buy a manometer pf and a new, adjustable
OPV and sort things out that way.


--
Alan

alanfrew@coffeeco.com.au
www.coffeeco.com.au




   
Date: 28 Nov 2006 10:41:22
From: Andy Schecter
Subject: Re: hooked up a new pump to my silvia
Coffee for Connoisseurs wrote:
> It would be cheaper to buy a manometer pf and a new, adjustable
> OPV and sort things out that way.

But that will do nothing to solve his problem.

--


-Andy S.

http://www.flickr.com/photos/andy_s/sets/


    
Date: 28 Nov 2006 11:10:10
From: Coffee for Connoisseurs
Subject: Re: hooked up a new pump to my silvia
>But that will do nothing to solve his problem.

I forgot to mention, with an original type ULKA pump. I still can't see the
reasoning for replacing the cheap, ubiquitous original one. You want to play
with brew pressure, buy a manometer pf & adjustable OPV, but right now he's
stuffing around with water debit. Even if he manages to fluke 9 bar or
whatever, 50ml/sec @9 bar is still too much.


--
Alan

alanfrew@coffeeco.com.au
www.coffeeco.com.au




     
Date: 28 Nov 2006 12:24:38
From: Andy Schecter
Subject: Re: hooked up a new pump to my silvia
Coffee for Connoisseurs wrote:
> I forgot to mention, with an original type ULKA pump.

OK, I understand you.

> I still can't see the reasoning for replacing the cheap,
> ubiquitous original one.

It's cheap and ubiquitous. Isn't that reason enough to replace it? :-)

But seriously, it's annoyingly noisy, too.

--


-Andy S.

http://www.flickr.com/photos/andy_s/sets/


 
Date: 24 Nov 2006 16:37:38
From: Alex_chef2000
Subject: Re: hooked up a new pump to my silvia

Well, another issue is that you should adjust your coffee grinder after
the pump replacement.

When you replace a pump, the water pressure also changes and you may
need to adjust your grounds as if all your equipment were new. It takes
time, but you will have real good espresso again.



Regards from Mexico,


Alex.:



 
Date: 24 Nov 2006 04:57:40
From: daveb
Subject: hooked up a new pump to my silvia
Is it gonna make BETTER coffee?



 
Date: 23 Nov 2006 13:56:29
From: Randy G.
Subject: Re: hooked up a new pump to my silvia, something's wrong
Putting together what Andy and Jim said, I think you will find the
problem. if it isn't a steam-related problem caused by a to high brew
temp, it is probably the way the pump is set up. Remember that you
have two factors with any water pump- volume and pressure. They have
to be thought of as independent factors. A pump that can operate at
130psi can deliver one ounce per hour at 130psi or it can deliver 100
gallons per minute at 130 psi. The gicleur is probably what you need.
The stock vibratory pumps cannot pump any where near the volume that a
rotary pump is capable of delivering and you need to regulate that
flow rate... I think.

Randy "I pump, therefore I am" G.
http://www.EspressoMyEspresso.com



dleary@gmail.com wrote:
>
>I bought a used fluid-o-tech pump off of ebay, and I have hooked it up
>to my Silvia.
>
>I did this priily because I wanted to have better control over the
>brew pressure, and many iterations of taking apart Sylvia's
>over-pressure valve and testing seemed like a pain.
>
>Anyway, the setup is all hooked up and 'works'. The problem is that
>when I start a shot, I get a quick 'splash' of water/coffee coming out
>of the portafilter, half an ounce or so, before the stream settles down
>to a normal rate for the rest of the shot. It tastes awful.
>
>I have a pressure gauge right after the pump (before the line goes into
>silvia), and the pressure looks ok, but the problem remains... I have
>adjusted the pressure as low as 7 bar, as high as 11, no real
>difference.
>
>Anyone have any ideas?


 
Date: 23 Nov 2006 21:31:21
From: Andy Schecter
Subject: Re: hooked up a new pump to my silvia, something's wrong
dleary@gmail.com wrote:
> I bought a used fluid-o-tech pump off of ebay, and I have hooked it up
> to my Silvia.
>
> I did this priily because I wanted to have better control over the
> brew pressure, and many iterations of taking apart Sylvia's
> over-pressure valve and testing seemed like a pain.
>
> Anyway, the setup is all hooked up and 'works'. The problem is that
> when I start a shot, I get a quick 'splash' of water/coffee coming out
> of the portafilter, half an ounce or so, before the stream settles down
> to a normal rate for the rest of the shot. It tastes awful.
>
> I have a pressure gauge right after the pump (before the line goes into
> silvia), and the pressure looks ok, but the problem remains... I have
> adjusted the pressure as low as 7 bar, as high as 11, no real
> difference.
>
> Anyone have any ideas?


Hard to say without directly observing your setup, but....

Procon and/or F-O-T pumps ramp up to pressure very quickly, much faster than
the vibe pump you replaced. This slams the puck and may cause channeling and
uneven extraction.

Measure how much water you get from the group in 10 seconds without the
portafilter in place (this measurement is also known as "water debit"). You
should get somewhere around 65ml-90ml.

If you're getting a lot more, this could be the problem. The cure is to
install an orifice ("gicleur") or a needle valve after the pump to throttle
the initial spurt.
--


-Andy S.

http://www.flickr.com/photos/andy_s/sets/


 
Date: 23 Nov 2006 11:09:24
From: jggall01
Subject: Re: hooked up a new pump to my silvia, something's wrong

dleary@gmail.com wrote:

> Anyway, the setup is all hooked up and 'works'. The problem is that
> when I start a shot, I get a quick 'splash' of water/coffee coming out
> of the portafilter, half an ounce or so, before the stream settles down
> to a normal rate for the rest of the shot. It tastes awful.
>

Try doing a quick bleed of the boiler by briefly opening the
steam/water valve just before starting the shot. Let it flow for a
second or so - just enough to purge.

If that makes the problem go away, then it could be related to a
too-high boiler temperature rather than the new pump.

Jim