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Topic: AutoFill Diagnosis Question (25 msgs / 566 lines)
1) From: dave
My machine pulls about 3 to 4 shots from a cold start w/o problems.  
With each shot the pump runs. Then any other attemp after the 3-4  
shots results in nothing but steam coming out of the head and pump  
doesn't run. If I turn the machine off and let it cool it pulls 3-4  
shots and repeats the same problem. I've gotten several diagnostic  
opinions on this from a pressure stat problem to an AutoFill problem.  
Anybody with experience on this subject would be greatly appreciated.

2) From: dave
Some Additional info: It is an Bezzera 99S/K HX machine and pressure  
readings are maintained at 0.9 to 1.2 bars at all times.
On Dec 30, 2006, at 6:27 PM, dave wrote:
<Snip>

3) From: Leo Zick
Shouldn't the machine warm up for at least 20mins if it's an HX?  If I try
to run mine from a cold start, water will dribble out, and itll be cold.
Have you ever descaled? Pressurestat sounds like it could be it, since it
should cut out when machine is up to temp. maybe its cutting out early?
Clogged or scaled?

4) From: dave
machine has no scaling on it at all, no clogs since I can get 3-4  
shots initially  and warm up is relatively quick on my machine.  
besides if I wait to long, we wont have any coffee in the am.  
Generally I wait until the pressure is built up which is about 5 to  
10 minutes on my machine then pull shots . Thanks for reply
On Dec 30, 2006, at 6:46 PM, Leo Zick wrote:
<Snip>

5) From: miKe mcKoffee
Since your machine is an HX neither auto-fill nor pstat have anything to do
with water flow through the HX and hence through the group. The HX water
plumbing is totally separate from the boiler, (but yes heated by running
through the boiler.) 
Whether dying pump (possibly over heating rapidly and shutting down), bad
reservoir water level sensor, flakey gicar (or whatever brand "brain") or
who knows what hard to say. Would take systematic troubleshooting. In truth
since your apparent understanding of the machine's mechanics seems limited
I'd take it to a reputable espresso machine technician.
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.
<Snip>

6) From: miKe mcKoffee
<Snip>
<Snip>
Highly doubtful. Water should flow through HX with pstat totally
disconnected and heater off. You'd just get cold water pumping through the
group. The pstat simply controls the heating element, heating to a certain
boiler pressure then turning off the heater circuit, turning back on when
boiler pressure drops to a given set point. Pstat has nada to do with HX
water flowing. The symptom is the pump not pumping water through the HX
after 3 or 4 shots. 
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.

7) From: Leo Zick
I thought the pstat controls water temp of the hx line, but my mistake,
that's the gicar, right?

8) From: dave
  My hunch is that something is changing value over time as heat is  
introduced, otherwise why would it work consistently when I let the  
machine cool. Since Brain Box, Giemme, sits next to the boiler(almost  
touching it) there must be some resistor or circuit thats affected. I  
may try to move the Brain to the outside of the housing and run a  
small fan over it to see if the machine will perform over a longer  
time-span. Generally if the pump was the issue wouldn't it just not  
work at all? Thanks for the responses!
On Dec 30, 2006, at 9:55 PM, miKe mcKoffee wrote:
<Snip>

9) From: dave
The pump not pumping after 3-4 shots is the symptom. What tells the  
pump to run when you pull a shot? Is it the Brain? Remember, the  
pressure
remains stable. Something changes value as temp/time increase.  
Perhaps , Mr. Voltmeter can shed some light on issue?
On Dec 30, 2006, at 10:05 PM, miKe mcKoffee wrote:
<Snip>

10) From: miKe mcKoffee
<Snip>
Yes the pstat "determines" (but not controls) the heating of the HX line by
controlling the heating element heating of the boiler through which the HX
line runs. However like I said, hot or cold the pump should run and water
should flow through the HX line.
miKe

11) From: Michael Dhabolt
Dave,
At the point in time when the machine will no longer pull shots......does it
still maintain the 0.9 to 1.2 Bar steam pressure (open the steam valve and
let the boiler pressure drop to below 0.9 Bar - does it come back up
to 1.2Bar?) ? If the boiler pressure comes back up to
1.2 Bar......you have confirmed that the Pstat is OK.
Again, at the time when the machine will no longer pull shots,.......If you
use some hot water from the tap or use a bunch of steam, does the pump start
and auto-fill the boiler?  I'm expecting that before you pull the 3 or 4
shots and the machine starts presenting the unusual behavior, that
the boiler auto-fills normally, but after the 3 or 4 shots it will not.  Am
I right, or wrong?
Your comment about Mr. Voltmeter is probably the next step.  If I'm right
about the previous question......I would check power going to the pump when
you expect pump activity.  If you have power to the pump, but it is not
running - it's the pump.  A quick google search for your machine, does not
answer my question of whether it uses a rotary or vibratory pump.  If it's a
vibratory....order a new one.  If it's a rotary, remove the pump from the
motor and retest to see if the motor runs, and the pump is locking up after
the 3 or 4 shots (unlikely but possible).
If, however, your voltmeter test tells you that there is no power to the
pump at this point - - the problem is probably on the 'brain' board or wire
termination between the board terminals and the pump (check terminals at the
board- slightly loosen and retighten - recheck).  A few machines have a
pump relay that is not mounted to the main board of the Giemme,  but chances
are that yours is.  With commercial machines this relay is responsible for
90% of 'brain' replacements.  If your safety and electronics skills are up
to it....you can check the control and power signals at the relay on the
board under the failure conditions.  If you are getting good control signals
but no power you can replace the relay (soldering skills required) on the
board or even solder wires to where the relay is mounted and install a
different (but similarly rated) relay outboard of the box.  If the control
signal to the relay is affected by the anomoly - break out your check book,
the Giemme is pretty expensive.  By the time the 'brain' starts exhibiting
these symptoms.......moving it to a cooler location is probably not going to
solve the problem (can't loose anything by trying).
If all of the above convinces you that the Giemme is the problem, the only
alternative to replacement is repair.  Do you have a local computer tech
that you have confidence in?  These things are pretty rudimentary technology
and a sharp tech (my local guy is semi-retired ex Air Force Tech that is
comfortable in a fix-it rather than replace-it environment) can trouble
shoot and fix it at the chip level.  If you find someone to do this.....have
them replace the relay while they are at it (even if it isn't currently
bad).
Mike (just plain)

12) From: Eddie Dove
Very instructive ... well done.
Eddie
On 12/31/06, Michael Dhabolt  wrote:
<Snip>
-- 
My Home Coffee Roasting Blog and Profiles for the Gene Cafehttp://southcoastcoffeeroaster.blogspot.com/

13) From: Michael Dhabolt
Eddie,
Thank you sir.
Mike (just plain)

14) From: miKe mcKoffee
This is a multi-part message in MIME format.
BZ99S vibe pump. Here's a sight with full parts break down diagrams in pdf:http://barazi.com.au/content/view/43/218/(Guess my Google trumped your Google:-)
miKe  
From: homeroast-admin
[mailto:homeroast-admin] On Behalf Of Michael Dhabolt
Sent: Sunday, December 31, 2006 12:10 PM
To: homeroast
Subject: Re: +AutoFill Diagnosis Question
Dave,
 
At the point in time when the machine will no longer pull shots......does it
still maintain the 0.9 to 1.2 Bar steam pressure (open the steam valve and
let the boiler pressure drop to below 0.9 Bar - does it come back up to 1.2
Bar?) ? If the boiler pressure comes back up to 1.2 Bar......you have
confirmed that the Pstat is OK.
 
Again, at the time when the machine will no longer pull shots,.......If you
use some hot water from the tap or use a bunch of steam, does the pump start
and auto-fill the boiler?  I'm expecting that before you pull the 3 or 4
shots and the machine starts presenting the unusual behavior, that the
boiler auto-fills normally, but after the 3 or 4 shots it will not.  Am I
right, or wrong? 
 
Your comment about Mr. Voltmeter is probably the next step.  If I'm right
about the previous question......I would check power going to the pump when
you expect pump activity.  If you have power to the pump, but it is not
running - it's the pump.  A quick google search for your machine, does not
answer my question of whether it uses a rotary or vibratory pump.  If it's a
vibratory....order a new one.  If it's a rotary, remove the pump from the
motor and retest to see if the motor runs, and the pump is locking up after
the 3 or 4 shots (unlikely but possible). 
 
If, however, your voltmeter test tells you that there is no power to the
pump at this point - - the problem is probably on the 'brain' board or wire
termination between the board terminals and the pump (check terminals at the
board- slightly loosen and retighten - recheck).  A few machines have a pump
relay that is not mounted to the main board of the Giemme,  but chances are
that yours is.  With commercial machines this relay is responsible for 90%
of 'brain' replacements.  If your safety and electronics skills are up to
it....you can check the control and power signals at the relay on the board
under the failure conditions.  If you are getting good control signals but
no power you can replace the relay (soldering skills required) on the board
or even solder wires to where the relay is mounted and install a different
(but similarly rated) relay outboard of the box.  If the control signal to
the relay is affected by the anomoly - break out your check book, the Giemme
is pretty expensive.  By the time the 'brain' starts exhibiting these
symptoms.......moving it to a cooler location is probably not going to solve
the problem (can't loose anything by trying). 
 
If all of the above convinces you that the Giemme is the problem, the only
alternative to replacement is repair.  Do you have a local computer tech
that you have confidence in?  These things are pretty rudimentary technology
and a sharp tech (my local guy is semi-retired ex Air Force Tech that is
comfortable in a fix-it rather than replace-it environment) can trouble
shoot and fix it at the chip level.  If you find someone to do this.....have
them replace the relay while they are at it (even if it isn't currently
bad). 
 
Mike (just plain)

15) From: Michael Dhabolt
miKe,
You must have used that new fangled long distance Google to get the
australian listing;~)  I still couldn't find the '/K' model.
Mike (just plain)

16) From: miKe mcKoffee
This is a multi-part message in MIME format.
Yeah, never found a /K variant either. Didn't visit the German (and other
non-English) site hits though.
 
miKe  
From: homeroast-admin
[mailto:homeroast-admin] On Behalf Of Michael Dhabolt
Sent: Sunday, December 31, 2006 4:01 PM
miKe,
 
You must have used that new fangled long distance Google to get the
australian listing;~)  I still couldn't find the '/K' model.
 
Mike (just plain)

17) From: dave
Mike(just plain?),
    Thank you for a  response so clean and thorough. I'm going in  
with the voltmeter monday to find some better answers. Your thinking
is mucho appreciated!
   I will respond to your question ASAP.
   Dave
<Snip>

18) From: Michael Dhabolt
Dave,
Hope it helps, and that the problem is on the less expensive side of things.
One addition would be.....when the machine gets to the point of not
initiating pump flow (after 3 or 4 shots)......stay aware that you don't
want the boiler level to get too low (such as during testing the auto-fill
circuit).....uncovering the heating element in the boiler is an immediate
hit to the bank account......better to turn it off, let it cool, and be sure
it fills the boiler to the proper level when you turn it back on before
continueing with the job.
Mike (just plain)

19) From: miKe mcKoffee
This is a multi-part message in MIME format.
Am I mistaken or missing something? Couldn't you just totally disable the
heating element for trouble shooting since the problem as reported is the
pump not working after 3 or 4 shots and no HX water flow? I'd simply unplug
the pstat circuit so it wouldn't tell the heating element to come on.
 
I believe the original post subject title was/is misleading caused by
erroneous input from some unknown source(s) given to Dave. Autofill doesn't
apply to the HX plumbing but rather the boiler and of course the boiler
doesn't feed the group/shot in an HX machine! Again, or am I mistaken? I
don't think so.
 
miKe  
From: homeroast-admin
[mailto:homeroast-admin] On Behalf Of Michael Dhabolt
Sent: Monday, January 01, 2007 12:21 AM
To: homeroast
Subject: Re: +AutoFill Diagnosis Question
Dave,
 
Hope it helps, and that the problem is on the less expensive side of things.
 
One addition would be.....when the machine gets to the point of not
initiating pump flow (after 3 or 4 shots)......stay aware that you don't
want the boiler level to get too low (such as during testing the auto-fill
circuit).....uncovering the heating element in the boiler is an immediate
hit to the bank account......better to turn it off, let it cool, and be sure
it fills the boiler to the proper level when you turn it back on before
continueing with the job. 
 
Mike (just plain)

20) From: dave
Mike,
   Thanks for all your input. I took the housing off and ran some  
voltage checks. I pulled the leveling probe out buy a few mm and  
tinkered around with it checking connections etc. and low and behold  
it ran for until I turned it off. Yippeeeee! Hope that continues. Not  
sure why other than pump connector.  Hope tomorrow will result in  
more of the same!!
   Is there a way to find out if the leveling probe should be exposed  
by so many mm? Also, not sure how to adjust pressure and temp now.  
Just flush the head if shes be idle for over4 min and surf unknown  
temp? Is there a methodically way to approach the perfect temp on an  
HX machine that only has a pressure gauge?
   I know its a new question but its also a new year. Happy new year!
  dave
On Dec 31, 2006, at 10:20 PM, Michael Dhabolt wrote:
<Snip>

21) From: Dan Bollinger
<Snip>
Dave,  Someone else had this same problem here, or perhaps on alt.coffee, about 
3 months ago.  When they tried my suggestion of raising the autofill sensor it 
worked for them, too.  The reason being that partial immersion of the HX 
extended its recovery time.  Sorry I didn't begin reading this thread until this 
am to save you some heartache. Dan

22) From: dave
Dan,
   I think when FedEx slammed this puppy around the sensor must have  
slid in. I ran it this am with no problem.
   dave
On Jan 1, 2007, at 4:10 AM, Dan Bollinger wrote:
<Snip>

23) From: Michael Dhabolt
Dave,
The 'new question'.  An article at Home Barista "How I stopped worrying and
learned to love HXs" at http://tinyurl.com/tp8f7*does a good job of
explaining the methodology and is a good starting place.
As far as the auto-fill probe depth into the boiler goes....I usually try to
set it around 3/4 full of water.  As far as finding the actual measurement -
?? - if you find some place that tells that spec. , let me know.
And miKe is correct, regarding the auto-fill circuits relationship to your
original problem of the pump not running after pulling 3 or 4 shots.
There are two situations (entirely separate) that provide a control signal
that tells the pump relay to power up the pump.
One of those situations is, of course, auto fill....the probe is no longer
touching water and completing the circuit that tells the machine that it has
enough water in the boiler......when that happens (circuit open) it sends a
control signal to the pump relay (start pump) and the boiler fill solenoid
valve (open valve).  When the boiler levels increases and the water touches
the probe.....circuit closed....pump relay/pump off....fill valve
closed........until next time.
The second, separate, situation that starts the pump is when you initiate
pulling a shot.  On your machine you are touching a keypad that sends a
signal to the Giemme 'Brain', on some semi-auto machines the signal comes
from a rocker (or other mechanical) switch, on some others it comes from a
microswitch being manipulated by various linkages and levers fixed to the
group head.  Wherever this signal comes from, it is routed to the pump relay
to start the pump and also is routed to the three-way valve to shift it into
position so that brew pressure water flows thru the group head into the PF.
At the end of the 'Pull' that signal is interrupted (either physically by
the Barista, or electronically by the 'Brain'), and the pump relay is
de-energized - stopping the pump and the three way valve de-energizes
shifting it into position to vent (into the drain tray) the area above the
PF in the group head.
On some itterations of the different 'Brain' boxes there is a safety
interlock that disables the pump after it has run for X (various amounts of
time) length of time.  This is usually implemented only on large commercial
machines and can also throw a relay to kick the power to the heaters off.
It is my understanding that this has kept some shop owners from opening
their doors in the morning and being presented with burnt out heaters and/or
a flood on the floor.  In my experience, this is the only situation where
both of the two pump control situations are commonly controlled.  If anyone
knows of others, I would appreciate being instructed.
And for the real technical stuff.....sometimes the machine decides it needs
a little TLC and confirmation that the Individual on the other end of the
buttons and levers is committed to the endeavor.  Sometimes, presenting the
machine with a few tools such as a screwdriver or two, removing a little
body work and wiggling a few wires convinces the machine to cast out the bad
gremlins because it is dealing with the right kind of folks.
Mike (just plain)

24) From: Dan Bollinger
This is a multi-part message in MIME format.
The depth of the autofill probe is not what is important. What is =
important is how much water covers the HX element inside the boiler. You =
want the HX to be substantially immersed even when the boiler level is =
at its lowest just prior to an autofill cycle.  How much the probe =
extends into the boiler is going to depend on the boiler configuration =
and the autofill circuitry.  Dan
  As far as the auto-fill probe depth into the boiler goes....I usually =
try to set it around 3/4 full of water.  As far as finding the actual =
measurement - ?? - if you find some place that tells that spec. , let me =
know. 

25) From: Michael Dhabolt
Dans comment identifies 'IN FACT' the important criteria.
Thanks Dan
On 1/1/07, Dan Bollinger  wrote:
<Snip>
Mike (just plain)


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