Posted Thu Aug 19, 2004, 5:09pm Subject: Re: Gaggia Coffee won't brew. A technical question.
Ardy, I still think it's pretty rough to assume straight away that Mike wouldn't be able to tell his machine was making espresso at 3 bar (the normal relief pressure of the spring valve, I've been told) vs 9bar.
As for your Gaggia's low brew temp (they don't seem to suffer from that on our models based on my comparison with a 3 group Azkoyren, drinking straight espressos), have you tried cheating it by setting it to steam mode for a few seconds before brewing to boost the temp? Obviously, you would need to experiment with the boost time and always do it when the OK to brew light just switches on for consistency.
Posted Thu Aug 19, 2004, 5:18pm Subject: Re: Gaggia Coffee won't brew. A technical question.
Ardy, I still think it's pretty rough to assume that Mike can't tell the difference between a shot brew at 9 bar and one brewed at 3 bar (the spring valve's normal release pressure, I've been told).
As for the limits of your Gaggia, the solenoid makes no difference at all to espresso quality, the tiny boiler won't screw a double shot (maybe the 3rd onwards if you don't let it recover, which it does very quickly since it's tiny) and you could try cheating the brew temp by switching to steam mode for a few seconds prior to boost the temp - of course, you will need to experiment to establish exactly how long you need to boost and always boost when the brew OK light comes on to be consistent.
Strangely, our downunder Gaggias (or at least mine) don't suffer from such a low temp (based on measuring the water temp and a direct comparison with a 3 group Azkoyen, drinking straight espressos as well as lattes).
So many threads here... not sure which one to weigh in on! I just completely disassembled a Gaggia "Espresso" model that was suffering an identical set of symptooms and still can't get water to flow. I have adequate steam pressure that is plenty hot, tried swappign the pump with another Ulka pump that is know to be working properly and all that was done after through grouphead cleaning etc.
Finally disassembled the boiler - there was a small bit of loosened scaling in the base of the boiler but not much and no corrosion. I'm a bit muystified about the hex nut people are describign that holds some sort of springball valve assembly I removed the grouphead ass)embly to clean and replace the gasket (which was shoht) and there are two openings up underneath behind the plate that pulls off this is the plate that is attached to the underside fo the boiler with two hex screws - same plate that the dispersion screen screws onto). Of these two openings one is threaded and empty - there was nothing in it when I got the unit open - no screw. The other goes up into the brass tube that sits inside the boiler. I've tried a paper clip end and a large common pin from both top and bottom but can't get anythign more out (there were a few pices if scale that initially came out of the top of the brass tube inside the boiler and a bit of sludge that dripped out the bottom. On the "Espresso" model there does nto appear to be any way to release and remove the springball valve to clean it. Is this possible? Perhaps it's different from the Classic and Coffee models?
I have a similar problem with a Gaggia Coffee. I believe it has all the symptoms Mike describes – I can pump water through the steam wand, but it will not pump water through the grouphead.
I have tried a new pump, just in case the original pump (even though it seemed to be working) had lost some pressure, but the result is exactly the same, so I have eliminated the pump as the source of the problem. This might suggest some kind of blockage elsewhere.
However, I have also taken everything apart, and cleaned all the components of the boiler and grouphead, so there are certainly no major obstructions.
On the basis of Mike’s experiences, I have tried the same trick of installing the springball valve assembly with the lower component unscrewed by a few turns, as the slight reduction in spring pressure seems to have made the difference in Mike’s case. However, this does not help on my machine.
(Incidentally, if I remove the spring and rubber ball entirely, then the water flows through fine, as you would hope(!), so there don’t appear to be any large deposits blocking any of the small channels in the system).
This leads me to my question, which also applies in Mike’s case – is it really possible for the springball valve assembly to have failed in some way which would cause this, or is the problem likely to lie somewhere else? I have cleaned the valve assembly, and there are no obvious signs that would indicate that it wouldn’t work properly.
I have also discovered, however, that when the pump is running, the water is being pumped out of the tube which comes from the fitting on top of the boiler (i.e. the arrangement which supplies the steam wand), and back into the water tank. I have to confess that this is the part of the machine that I am not too familiar with, but I assume that this is some kind of pressure release valve.
Could this mean that it is this release valve which has failed, and is simply letting water through at a lower pressure than it should, rather than there being a blockage elsewhere? (Or have I misunderstood this part of the machine?)
Any help would be greatly appreciated, as this has me stumped!
If the pump is to weak to push past the shower head valve, then it won't get much past the safety valve. IF the water is diverting into the water tank, then the safety valve might be damaged and not presenting enough resistance or the shower head ball and spring might be sticky or under too much tension. If the shower head valve has too little tension, you won't get decent performance from the frother because too much will bypass into the shower head.
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