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Date: 22 Jan 2007 16:14:22
From: joe
Subject: Oscar's pump
My NS Oscar has lost its brewing pressure. Nothing comes through "normally"
ground coffee. Without coffee there is very litlle water coming when the
machine is cold (about 60 cl in 20 seconds) and nothing but steam when the
machine is warm.

I descaled the whole system and noticed that filling the boiler takes a
really long time; the pump switches off after 90 seconds and that happens
two or three times before the boiler is full.

I disconnected the tubing going onwards from the pump and run just the pump.
It gave me about 110 cl in 20 seconds. That seems bit low to me. Is it safe
to assume that the pump is dying and get a new one?

Jura





 
Date: 30 Jan 2007 06:05:07
From: daveb
Subject: Re: Oscar's pump
yup. they commonly get louder and louder as they approach failure.

d



 
Date: 30 Jan 2007 08:54:59
From: joe
Subject: Re: Oscar's pump
I bought a 48 W ULKA pump last week. It solved the problem; I now get
about 100ml in 10 seconds through the grouphead. The noise of the pump
is definately less harsh than what it was lately with the old one.

Jura



 
Date: 22 Jan 2007 13:05:14
From: chardinej
Subject: Re: Oscar's pump
> chardinej <chardine@nbnet.nb.ca> wrote:
> >
> > Perhaps after the descaling some of the plumbing in the Oscar is clogged with bits of
> > scale?
>
joe wrote
> I cannot se any scale inside the pump. And as the 110 *ml* is measured
> directly from the pump the plumbing wouldn't affect the water flow even
> if it was clogged.

Joe- The suggestion of scale bits in the system was to attempt to
explain why you were only getting 60ml per 20 s through the group head
and double that from the pump directly. I've read some threads on pump
output on the Oscar and it does not seem to be too consistent between
machines. Perhaps 110 ml in 20s out of the pump is quite fine and your
pump is OK. The problem still could be that you are clogged with scale
bits between the pump and the group head. This route includes some
pretty small ID copper pipe, some bends, and of course the heat
exchanger itself, not to mention the small hole in the group head. It
sounds depressing but a friend in the coffee business here (he
maintains commercial machines) told me not long ago that by the time
you think you have to descale an expresso machine, it's too late, and
all it ends up doing is dislodging bits of scale that cause problems
elsewhere (hope I got that right Terry). Best practice is to only use
good water of the correct softness from day one and scale should not be
an issue.

John



  
Date: 23 Jan 2007 18:31:28
From: joe
Subject: Re: Oscar's pump
chardinej <chardine@nbnet.nb.ca > wrote:

> Joe- The suggestion of scale bits in the system was to attempt to
> explain why you were only getting 60ml per 20 s through the group head
> and double that from the pump directly. I've read some threads on pump
> output on the Oscar and it does not seem to be too consistent between
> machines. Perhaps 110 ml in 20s out of the pump is quite fine and your
> pump is OK. The problem still could be that you are clogged with scale
> bits between the pump and the group head.

That is a valid point. However, if I remember correctly I once
measured 90ml in 10 seconds from the grouphead. Furthermore, the
sound of pump doesn't change after couple of seconds when brewing
as it has done earlier (after it has built up the pressure).

Anyway I removed the pump and will get a new one tomorrow. The old
pump is made by C.E.M.E and is a 53 W model. There isn't anything
about the max pressure, but I assume it is 15 bar. I called a repair
shop nearby and they told that they have 48 W and 54 W ULKA pumps
(max 15 bar). The guy suggested getting the 48 W model but based on
the rating of the old motor I think I'll get the 54 W one.

Jura




   
Date: 23 Jan 2007 19:07:19
From: Robert Harmon
Subject: Re: Oscar's pump
Worth noting - the lower watt pumps are quieter & the pressure is the same.
--
Robert (Gig 'em!) Harmon
http://tinyurl.com/pou2y
http://tinyurl.com/psfob
http://tinyurl.com/fkd6r

"joe" <joe@invalid.fi > wrote in message
news:45b65480$0$8959$ba624cd0@newsread.funet.fi...
> chardinej <chardine@nbnet.nb.ca> wrote:
>
>> Joe- The suggestion of scale bits in the system was to attempt to
>> explain why you were only getting 60ml per 20 s through the group head
>> and double that from the pump directly. I've read some threads on pump
>> output on the Oscar and it does not seem to be too consistent between
>> machines. Perhaps 110 ml in 20s out of the pump is quite fine and your
>> pump is OK. The problem still could be that you are clogged with scale
>> bits between the pump and the group head.
>
> That is a valid point. However, if I remember correctly I once
> measured 90ml in 10 seconds from the grouphead. Furthermore, the
> sound of pump doesn't change after couple of seconds when brewing
> as it has done earlier (after it has built up the pressure).
>
> Anyway I removed the pump and will get a new one tomorrow. The old
> pump is made by C.E.M.E and is a 53 W model. There isn't anything
> about the max pressure, but I assume it is 15 bar. I called a repair
> shop nearby and they told that they have 48 W and 54 W ULKA pumps
> (max 15 bar). The guy suggested getting the 48 W model but based on
> the rating of the old motor I think I'll get the 54 W one.
>
> Jura
>
>




    
Date: 23 Jan 2007 19:56:36
From: joe
Subject: Re: Oscar's pump
Robert Harmon <r_h_harmon@zhotmail.com > wrote:
> Worth noting - the lower watt pumps are quieter & the pressure is the same.

That is definitely worth considering, the old pump was annoyingly loud.

Here is why I thought about getting the pump with similar watt-rating as
the old one: The pressure and the flow from a pump go hand in hand. The
higher the pressure the smaller the flow and vice versa. So when getting
a replacement pump we should know the flow/pressure charasteristics of the
pump. I would assume pumps with similar power would have similar
charasteristics.

Someone with more knowledge could tell whether such power differences
(and thus flow/pressure differences) would actually make any difference
(to the taste of the coffee).

Jura


     
Date: 24 Jan 2007 03:47:07
From: daveb
Subject: Re: Oscar's pump
any Ulka pump will do.


"joe" <joe@invalid.fi > wrote in message
news:45b66874$0$8948$ba624cd0@newsread.funet.fi...
> Robert Harmon <r_h_harmon@zhotmail.com> wrote:
>> Worth noting - the lower watt pumps are quieter & the pressure is the
>> same.
>
> That is definitely worth considering, the old pump was annoyingly loud.
>
> Here is why I thought about getting the pump with similar watt-rating as
> the old one: The pressure and the flow from a pump go hand in hand. The
> higher the pressure the smaller the flow and vice versa. So when getting
> a replacement pump we should know the flow/pressure charasteristics of
> the
> pump. I would assume pumps with similar power would have similar
> charasteristics.
>
> Someone with more knowledge could tell whether such power differences
> (and thus flow/pressure differences) would actually make any difference
> (to the taste of the coffee).
>
> Jura




     
Date: 24 Jan 2007 03:40:01
From: daveb
Subject: Re: Oscar's pump
just get any 41 watt Ulka pump. -- used in MILLIONS of machines

AND if your old pump was getting LOUD? typical of a failing pump.



"joe" <joe@invalid.fi > wrote in message
news:45b66874$0$8948$ba624cd0@newsread.funet.fi...
> Robert Harmon <r_h_harmon@zhotmail.com> wrote:
>> Worth noting - the lower watt pumps are quieter & the pressure is the
>> same.
>
> That is definitely worth considering, the old pump was annoyingly loud.
>
> Here is why I thought about getting the pump with similar watt-rating as
> the old one: The pressure and the flow from a pump go hand in hand. The
> higher the pressure the smaller the flow and vice versa. So when getting
> a replacement pump we should know the flow/pressure charasteristics of
> the
> pump. I would assume pumps with similar power would have similar
> charasteristics.
>
> Someone with more knowledge could tell whether such power differences
> (and thus flow/pressure differences) would actually make any difference
> (to the taste of the coffee).
>
> Jura




 
Date: 22 Jan 2007 09:20:21
From: chardinej
Subject: Re: Oscar's pump

Jack Denver wrote:
> 110 cl = 1100 ml (over a liter) in 20 secs = 55 ml/ sec (almost 2 oz) is
> more than ample - there is nothing wrong with the pump based on that flow
> rate. Unless you misplace a decimal? Did you mean ml not cl?


Out of the group head of my Oscar with no portafilter attached I get
125 ml in 10 s, or 250 ml in 20 s. If indeed the OP meant 110 *ml* in
20 s then this is less than half what I am getting. Perhaps after the
descaling some of the plumbing in the Oscar is clogged with bits of
scale? There is a small 1-way valve in the Oscar that stops hot water
from the boiler backflowing to the pump. I had to replace mine because
it had deteriorated. I've been told that vibe pumps don't like hot
water and will fail eventually if this valve is defective.

Vibe pumps aren't too expensive so maybe it would be best to replace?

John



  
Date: 22 Jan 2007 17:54:11
From: joe
Subject: Re: Oscar's pump
chardinej <chardine@nbnet.nb.ca > wrote:
>
> Jack Denver wrote:
>> Did you mean ml not cl?

Of course I did, sorry for that.

> Perhaps after the
> descaling some of the plumbing in the Oscar is clogged with bits of
> scale?

I cannot se any scale inside the pump. And as the 110 *ml* is measured
directly from the pump the plumbing wouldn't affect the water flow even
if it was clogged.

> Vibe pumps aren't too expensive so maybe it would be best to replace?

Yep. Oscar isn't imported to Finland anymore, but I'll call the NS
importer to see if thay have any spare parts left.

Jura



   
Date: 22 Jan 2007 19:20:12
From: JeeWee
Subject: Re: Oscar's pump

>
>> Vibe pumps aren't too expensive so maybe it would be best to replace?
>
> Yep. Oscar isn't imported to Finland anymore, but I'll call the NS
> importer to see if thay have any spare parts left.
>
> Jura
>
>

Hello,

There is an on-line Espresso part shop in Germany. I think they will ship
to Finland. I have very good experiences with this shop. They ship quickly
and prices are ok.

Here is the link:

http://www.espressoxxl.de

Good luck,

Greetings,

JW



 
Date: 22 Jan 2007 11:42:31
From: Jack Denver
Subject: Re: Oscar's pump
110 cl = 1100 ml (over a liter) in 20 secs = 55 ml/ sec (almost 2 oz) is
more than ample - there is nothing wrong with the pump based on that flow
rate. Unless you misplace a decimal? Did you mean ml not cl?





"joe" <joe@invalid.fi > wrote in message
news:45b4e2de$0$8954$ba624cd0@newsread.funet.fi...
> My NS Oscar has lost its brewing pressure. Nothing comes through
> "normally"
> ground coffee. Without coffee there is very litlle water coming when the
> machine is cold (about 60 cl in 20 seconds) and nothing but steam when the
> machine is warm.
>
> I descaled the whole system and noticed that filling the boiler takes a
> really long time; the pump switches off after 90 seconds and that happens
> two or three times before the boiler is full.
>
> I disconnected the tubing going onwards from the pump and run just the
> pump.
> It gave me about 110 cl in 20 seconds. That seems bit low to me. Is it
> safe
> to assume that the pump is dying and get a new one?
>
> Jura
>