La Pavoni Professional 16 Slow Water Draw

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LaPavoniFan

#1: Post by LaPavoniFan »

Hello,

I am wondering if anyone can help me. I have owned my La Pavoni Professional 16 cup for 7 years and have been maintaining it (replacing group head gaskets) regularly. About two months ago I started having an odd problem. The water comes into the group head much more slowly. I have to lift the lever almost all the way up, before the water starts flowing. There is no decreased pressure, according to the pressure gauge. I thought it was time to replace gaskets, but that did not fix the problem. The piston shaft appears to be fully screwed into the piston, so that doesn't seem to be the problem. I then read online that it may be time to replace the group head inner sleeve. I ordered one and replaced it, but the problem still persists.

wkmok1

#2: Post by wkmok1 »

Hello Maxim,

I can think of 2 possible causes for why you need to lift the lever higher than normal for water to come into the group.
1. The piston has worked loose from the shaft. It hangs lower at each position of the lever. I've read that this is common with plastic pistons.
2. The pin connecting the lever to the piston shaft is worn to a smaller diameter.

Hope this helps.
Winston

ojt

#3: Post by ojt »

Did you check the dipper tube (L-pipe)? It can sometimes crack and lead to this phenomenon.
Osku

jtrops

#4: Post by jtrops »

It really sounds like the "loose piston" problem to me.

This is worth checking regardless of piston material. FWIW I didn't ever have a problem with my plastic piston loosening, and replaced it after it cracked. A few months after replacement the brass piston started behaving exactly like what you are describing, and so I took it out, and gave it a very firm twist using a lid gripper to grab the piston and a screwdriver through the hole in the rod. That was years ago now, and I haven't had a problem since.

LaPavoniFan

#5: Post by LaPavoniFan »

Thanks, folks! The deeper tube seems fine, though there was a little rust at the top.

I immediately suspected that the shaft was loose. My piston and shaft are brass. I checked several times, and they seem tightly connected. In fact, I can't even unscrew it. It is weird, because this seems like th obvious suspect.

The pins seem fine. Not brand new but not thin or worn out looking.

User avatar
homeburrero
Team HB

#6: Post by homeburrero »

If not the usual suspects you might want to look for a scale obstruction inside the group. Very unlikely, but we did see a case of that years ago on the CoffeeGeek forums. In the image below, there was a scale blob in the ceiling of the group that was right above the little inlet channel in the sleeve, and was blocking flow.


(Image borrowed from: http://www.coffeegeek.com/forums/espres ... 011#566011 )
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

ojt

#7: Post by ojt »

Also if the water use has not been low mineral the pressure stat tube may be obstructed with scale and make it work unpredictably. Not sure though if it would usually rather overheat in this case but might be worth checking out.

One thing also about the L-tube. I think it's brass and hence should not rust... maybe it's corroded through? Perhaps change the tube anyway?
Osku

LaPavoniFan

#8: Post by LaPavoniFan »

Thanks, folks! I misspoke. The L-Pipe is not really rusted but a little calcified at one spot from the time I lived in a previous house, without RO water filtration system and was just relying on Brita. When I replaced the inner sleeve, I checked for dirt, calcification and blockages, and all seemed fine.

There is no calcification that is visible anywhere. We have a water softener and a RO water filtration system. So there is no calcification here.

After reading these posts, though, I am beginning to suspect that maybe the pipe connector needs to be looked at or replaced. Mine is black plastic (not brass). I haven't been able to remove it, because I don't have a 4-pin or 2-pin socket. Any pointers for how to best remove the pipe connector? What tools do you use? There is a special tool I see for La Pavoni, but it seems pricey. If I need to replace the connector, I will probably replace with brass and replace the L-pipe for good measure, too. It's getting to be a nearly brand new group head, so it seems like we are down to the connector and pipe as the likely suspects.

Thanks everyone!

jtrops

#9: Post by jtrops »

I hope the new pipe connector does the trick for you (and, if so I will make a note to check that if I ever have this problem)!

I'm a bicycle mechanic, and I have an adjustable pin spanner that I use for things like this. This one is the Park Tool SPA-6. There are much cheaper versions that would do fine for this job if you look for a "pin wrench."


LaPavoniFan

#10: Post by LaPavoniFan »

By the way, how often do the pipe connectors typically need replacing?