# Vivi HX leak - missing seal?



## daekis (Nov 27, 2011)

I apparently should never have taken the group head off my Vivi MKII for cleaning (I just couldn't get some of the dirt off). I need some advice, and apologies in advance for not knowing the correct terminology. Anyway. After re-assembly I have a leak, probably in the connection for the return water going back to the boiler. I get 10-15 drops of water per minute on the front of the machine from just under the group head. There is no water on the inside wall so presumably it is a poor seal between the group head and the "joint" (see picture below) as it doesn't fit very tight at all even with PTFE thread seal tape (12mmx0.075mm). I am certain there was no gasket when I took it off, yet I can't get it sealed and currently I am running very low on patience... Help!

When I detached the group head from the boiler, the thread on the return water "joint" looked like this:









The general assembly can be seen on page 3 of Bella Barista's closer look guide.

It seems to me there is space and a logical place for a gasket between "joint" component and the group head, yet there was none. Did I lose it? Also, no matter how much seal tape I use there certainly isn't a tight seal. Fully locked in puts the joint at 10 o'clock, at its target position of 6 o'clock I can feel the seal is quite loose.

What to do? Put a gasket in between? Get a thicker seal tape?

(I promise, this is the very final bit of the mini-rebuild, everything else looks good)

Thanks again!

Daniel


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## MelonCoffee (Jun 21, 2012)

From what i understand...you are suggesting a leak through the threads of the connection to the lower part of the group head (return to heat exchanger pipe) & if you tighten it fully it is in the wrong position?

Assuming I am correct: you need some form of thread lock (thread seal) compound to go on the threads. Ptfe tape can sometimes help but is never as good. I use one that a manuafacturer sends me and the bottle is all Italian so I couldn't tell you what it is - the only part i can understand is "C52"!! Loctite do something similar but ensure it is food safe & can cope with temperatures. Loctite 242 or Loctite 542 might be suitable. You can check datasheets on their website or drop an email to them to enquire as to suitability. Most set to a thermoset plastic which would be fine.

Good Luck!


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## daekis (Nov 27, 2011)

I am a software engineer (mostly manager even nowadays) so my experience with practical things is limited (oh yeah, my gf kept rubbing that in last night blaming me for the coffee machine not working!). Thanks a lot for sending me in the right direction. I indeed had to do a bit of data sheet research and found out that a thread sealant is different (pressure) vs a thread lock (movement, might not seal at all - all this stuff is news to me!) and that finding a food-grade one isn't all that easy, and as indicated, non-food grade ones can taste bad or even be toxic. Luckily I managed to come up with the right google search eventually and found that our American friends have already debated this extensively and a tube of food grade thread sealant Loctite 567 has been ordered. Cheers!


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