Gaggia Classic, poor flow through grouphead (again)

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andreafelix

#1: Post by andreafelix »

Hello!
I know this question has been asked so many times, but I couldn't find any solution :cry:

I'm getting very poor flow from the group, I've already:
- disassembled the machine and cleaned up the Solenoid valve
- replaced the Ulka pump

Nevertheless, I still have the issue

here a video:


What is the next check to be done?

many thanks

ciao
Andrea

JRising
Team HB

#2: Post by JRising »

How's the flow out the steam wand if you open the valve while it's struggling to put it through the grouphead? Can you hear the pump increase its stroke with the pressure change when the steam valve is open, ie. the pump is pumping against a high back-pressure until the steam valve is opened?
If so, then there is a partial blockage in the distributor disk area or in the 3-way valve.

andreafelix (original poster)

#3: Post by andreafelix (original poster) »

JRising wrote:How's the flow out the steam wand if you open the valve while it's struggling to put it through the grouphead?
Hello, thank you for replying

I tried and yes if I open the steam valve while the pump is already working for the group, it seems that the pressure changes like the pump can finally pumps the water somewhere... (check out this video if you like: http://www.youtube.com/watch?v=F8rPkXvtT1Q)

As I said in the firt post, yesterday I disassembled the machine following this video (http://www.youtube.com/watch?v=0ipvBdWaVzQ) and cleaned up the 3-ways valve (1h+ into decalc liquid). So i would exclude the culprit is the 3-ways valve...

You mentioned the distributor disk area, what do you mean exactly? this ?

JRising
Team HB

#4: Post by JRising »

The distributor disk area is the area that I can clearly see is very clean in that photo of the bottom with the distributor disk removed. So that's not the problem. You have it wide open enough that you can blow through all the ports and find out what does and does not allow flow. If the water flows easily through the steam valve, then it's flowing into the boiler just fine, Is the vertical pipe in the boiler possibly clogged? Can you blow through it when the brew valve is removed?

andreafelix (original poster)

#5: Post by andreafelix (original poster) »

JRising wrote:I can clearly see is very clean in that photo
Actually, that one is not mine, but I tried even removing the big disk and it doesn't change..
JRising wrote: Is the vertical pipe in the boiler possibly clogged?

You mean the one in the yellow box (pls see the attached image)?

JRising wrote:Can you blow through it when the brew valve is removed?
sorry, this is not clear to me

JRising
Team HB

#6: Post by JRising »

Yes. That pipe is where the water flows out of the boiler toward the "3-way Solenoid Brew Valve". It could possibly be clogged inside that pipe or below it between the pipe and the valve... With the valve removed from the boiler, can you blow air down that pipe? If you can blow down that pipe, the air will come out one of the holes that the 3-way valve was covering. Next, see if you can blow into the other hole that the valve was covering. What the valve does is allow that water leaving the boiler through to the other hole that takes it to the brew head. If both of those passages are clear, then the clog must be in the valve.

pizzaman383
Supporter ♡

#7: Post by pizzaman383 »

Have you checked whether water flows from the solonoid to the single exit hole in the group head where water exits to the top of the dispersion block (which typically has 4 holes)? Blockage in this path could be the problem.
Curtis
LMWDP #551
“Taste every shot before adding milk!”

andreafelix (original poster)

#8: Post by andreafelix (original poster) »

Thank you both for your input, I had to study a little how to understand how the machine works...

Now I know where to watch, basically it's the vertical pipe and following passages/holes: pipe --> solenoid valve --> group

thanks a lot indeed!

I'll let you know!
Andrea

this is taken from youtube (not mine)

andreafelix (original poster)

#9: Post by andreafelix (original poster) »

Hello!
Just a quick update, it's solved!

I disassembled pratically each component of the machine and, considering the machine is 8 yo, I found things in pretty good conditions. The veritical pipe had no scale attached and also the passage from the boiler to the solenoid valve was clear; the same for the internal passage in the group (from external to the disk area).

Eventually I had to get back to the solenoid valve itself, that BTW was the first part I checked in the past days

When I looked at valve initially, I had no experience at all so my examination was not done properly: I only descaled it for 30 mins aprox. Re-checking I found that the valve passage that connects the boiler to the group was clogged: so I had to work with a needle to remove the scale and the hole is not easily accessible; then I used a manual pump to remove as much scale as possible (I don't have a compressor). Then another descale soak. At the end of the process, the air flow was not as full as the one you get with the other hole in the solenoid valve (the passage vs the reservoir), probably because of the curve it has to pass through

After reassembling all the parts (BTW I found very useful this video: http://www.youtube.com/watch?v=N9i-EH7qXOc) I tried and it worked perfectly! I couldn't believe my eyes!

So I want to thanks JRising and pizzaman383 to have motivated me to continue the troubleshooting

thanks
Andrea