Leaking pressure relief valve mount (La Pavoni Pro pre-millennium)

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RobAnybody
Posts: 440
Joined: 4 years ago

#1: Post by RobAnybody »

Hi all,
I recently found out my pavoni has a small steam leak where the pressure relief valve is mounted on the body.
I noticed it first after I descaled the boiler a few weeks ago. Since then I would hear a slight hiss which would disappear when the boiler had completely heated up. At first I thought the pressure relief valve itself was the issue but upon disassembly it appeared to be clean.
Today the hiss lasted a bit longer than usual and upon inspection I noticed the small steam leak. Apparently it had been there even before I bought the machine as the location matches a 'water spot' on the boiler that was there when I got it (inside the circle).

Most likely descaling the boiler opened up the leak..
After a bit of searching I stumbled upon this thread;
La Pavoni Pro constant hissing from the OPV?
and since I don't particularly like the prospect of steam erosion making the leak worse I decided to address the issue.
Since I don't have a nice bent wrench and my 16mm conus wrench (I do most of my MTB maintenance myself) doesn't fit through the fill opening of the boiler I decided to remove the heating element and go in via the bottom.
This of course means that I also will have to replace the heating element gasket (first time the element came off since 1994) but it also allows me to address some residual scale clumps on the heating element sleeve and lower part of the boiler.
Besides the heating element gasket I also ordered a new sealing ring (No 45 on the schematic, part nr 313003) for the pressure relief valve (and some seals that will need replacing in the near future).
Is there anything else I need to take into account when going for the unmounting and re-assembly (Besides getting a fitting wrench to hold the nut inside the boiler)?
Thanks in advance!
Cheers!
Rob
LMWDP #647

RobAnybody (original poster)
Posts: 440
Joined: 4 years ago

#2: Post by RobAnybody (original poster) »

The new heating element gasket, sealing rings and o-ring I ordered arrived already this morning,
the rest of the repair will have to wait a bit until I can pick up a 16mm articulated socket wrench to hold the inner nut on the relief valve. Luckily I can borrow one from the lab were I work.
I've reassembled the valve for now so I can warm up the system by pouring in hot water in case I have difficulties unscrewing the valve body.

I also realised I should probably get better at making creative/interesting/sexy post titles

Anyways, if anyone has tips/suggestions things I should be weary off for this repair please let me know!
Cheers,
Rob
LMWDP #647

athoangphan
Posts: 162
Joined: 6 years ago

#3: Post by athoangphan »



I added a rubber gasket inside the boiler which created a tight seal preventing future leakage on my machine. I did the samething for the steam body. You could use the same plastic gasket used to create a seal between the sightglass retainer and the pressure gauge adapter, but after awhile you will have to tighten the inner bolt as the plastic gasket will form itself around the washer and shrink a bit due to heat, the rubber gasket works better and you could find them as Ace Hardware or Homedepot.

RobAnybody (original poster)
Posts: 440
Joined: 4 years ago

#4: Post by RobAnybody (original poster) »

Thanks for the suggestion!
I have a few high-temp rubber seals lying around in the lab, so
I can try those if I can't make the seal with the copper washer.
Cheers,
Rob
LMWDP #647

RobAnybody (original poster)
Posts: 440
Joined: 4 years ago

#5: Post by RobAnybody (original poster) »

I was able to unscrew the inner nut using a 16mm articulated socket wrench, cleaned up the valve seating on the body and re assembled with a new copper washer.
Also took care of some scale buildup in the lower part of the boiler around the heating element and on the heating element and the copper sleeve around it. Replaced the element gasket and re assembled the machine. She managed to stay dry during the cold test but there was some hissing near the heating element when inheated her up, so I gently tightened the bolts on the heating element (I read several warnings about over-tightening the element) which seemed to take care of that.
The valve body sealed nicely but the ball vale itself didn't so i spend an additional half an hour cleaning and polishing the valve body and steel ball (hadn't thought of getting the teflon mushroom to replace the ball when I ordered the rest of the supplies).
All in all she appears to be in working order again, though I always feel anxious for a few days after a repair like this, somehow there is always the fear of actually breaking things while trying to fix them.
I do have the feeling the base gets a bit hotter than before (no actual measurements, just a feeling) and I did notice some condensation in the front of the sub base. I did do a test running her with a paper tissue underneath the boiler but that came out dry. Also there is no hissing sound coming from the heating element when she is up to temperature and pressure.
Any suggestions on what might be causing this?
Thanks in advance!
Rob
LMWDP #647