Hot grouphead La Pavoni Pre-millenium Professional - Page 5

#41: Post by **homeburrero** » May 30th, 2020, 11:11 am

Essprezu wrote:I checked the label and it says 230v and 1000 watt.

So that's not your cause. (Good thing) No need in my opinion to check this further, but if you have a multimeter handy you could do a simple check that the element resistance is in the 53 ohm ballpark

Essprezu wrote:I did notice things: after 7 minutes the group starts to drip. And I also see steam coming out of the grouphead with little drops attached to the shower screen.

I agree with others, and think think that's your likely culprit. If your upper piston seal is failing to seal against the boiler pressure you will get water leaking out of the group at the shower screen, and this water is replenished by steam from the boiler, which transfers heat to the group. Condensing vapor can transfer a surprising amount of heat. As others said, your next step is a rebuild with a gasket/seal kit.

Essprezu wrote:I switched it back on and kept an eye on it. Now it has reached 75-80 degrees after fully pressurised.

Sometimes an old hard gasket will start to seal as it warms and softens - may cause an intermittent steam leak.

May 30th, 2020, 2:31 pm

IamOiman wrote:the gaskets if they are still good will be malleable/squishy and not be damaged when disassembling the group. If they are bad they are often brittle and will break, which by then is a good reason to replace. I have taken off my group many times without switching the seals and is very easy to do. You only need a 10mm and 14mm wrench to take apart the group.

The I want you to check is the group sleeve inside the grouphead. This may not be the cause of your dripping but it's good to see if the c-clip ring and gasket it holds is still good as that can often rust/corrode and leak from the top of the group. Another possibility is the piston gaskets are bad and pressurized water forces itself around the gasket and leak. I have blue cafelat silicon gaskets which are pretty easy to maintain compared to the rubber ones.

If the group is leaking this would explain the quick heatup as basically your machine is constantly flushing water through the group, which heats it up faster.
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Thanks so much! I'm going to order the gasket kit right away and try it out. No need for me to pry it open now, since if it turns out bad, I'll have to wait till the parts arrive.

June 11th, 2020, 11:27 am

I have finally replaced the grouphead gasketseals and what a difference in performance. Although I only used it once, it did multiple things: first of all I had to pull the lever all the way up for the water to rush through. At first use, after I purged the false pressure, the pressuregauge needle dropped all the way to zero to start over. At that moment, the temperature reached 90-95 degrees Celsius.
After use, I shut it off and the lever pulled itself all the way up. I was worried that I messed up somehow but I understood that as the hot air condensed, it created a vacuum.
I wish I could show you the pictures, but somehow I can't post them.

#44: Post by **IamOiman** » June 11th, 2020, 12:29 pm

Great to hear!

The lever going up after turning off the machine is normal since a small vacuum is formed from the cooling boiler as you noted. A gurgling noise accompanies this as well but you can open the steam valve to avoid it once the pressure goes down a little bit. It should not be harmful to the Pavoni either way.

June 11th, 2020, 5:27 pm

That's for sure! And again thank you for the advices in helping me out.

Obviously my thanks goes for everyone that contributed!

Now I can start making some espresso!

#46: Post by **guijan12** » June 12th, 2020, 8:54 am

Essprezu wrote:I have finally replaced the grouphead gasketseals and what a difference in performance. Although I only used it once, it did multiple things: first of all I had to pull the lever all the way up for the water to rush through. At first use, after I purged the false pressure, the pressuregauge needle dropped all the way to zero to start over. At that moment, the temperature reached 90-95 degrees Celsius.
After use, I shut it off and the lever pulled itself all the way up. I was worried that I messed up somehow but I understood that as the hot air condensed, it created a vacuum.
I wish I could show you the pictures, but somehow I can't post them.

Good to hear, congrats!

And I also learned something from following this thread.