Hi all, thanks for recent advice for pressurestat replacement on my Giotto. As mentioned on that thread, when I bought it, it was some 10 yrs old and never used, so this was my first p-stat malfunction.
Good news: The p-stat was the problem and the Giotto is back in operation.
Bad news: When testing, I noticed a slight steam leak from the top of the boiler, where the L connector (for water to brewhead) screws into the boiler. I'm sure that this causes more frequent cycles for the p-stat/heating element.

A couple questions:
What "plumbing goo" should I use on the threads? It seems that the goo has decomposed to allow minor steam escape.
Is there anything else in there (washer or compression fitting)? I'd hate to take it apart and find that I need additional part(s).
Any other advice? I recall from Silvia, that this sort of connection requires sealant because the male fitting that goes into the boiler has to orient in exact position for the downstream fittings

Thanks,
-Dirk

Alas, seems nobody has yet chimed in with expert help on this one. I have that same machine but don't have any direct experience - have never removed that fitting on the HX.

If it's a teeny leak, perhaps only after the pump kicks in, you might try just watching it and seeing if it won't self seal with scale after a little use. Or try a kludge - Using Loctite 290 to seal small cracks and pin holes in boilers

My guess is that the original goo is one of the Loxeal threadlockers (Stefano sells them, they are pricy) and possibly the one intended for fittings that are not often removed. Removing this L fitting and cleaning up the boiler threads may break loose some of that stuff which would fall inside the HX chamber. So you may need to remove the lower end (just the fitting on the injector and/or thermosyphon tube) so that you can flush it out real well.

I don't think there's any sort of washer in there, and based on this thread about a similar problem with an Andreja ( Fittings in the top of the boiler - Teflon tape or thread lock? ) it may be OK to first try with multiple turns of Teflon tape, using less or more as necessary to get the thing oriented right.

I think some high temperature teflon tape should do the trick. I'd hesitate to use any "goo" that might be fairly toxic.

Thanks for the input. A few weeks after replacing the p-stat and everything seems back to normal.
Homeburrero, as you suspect, it is a teeny leak and seems to be mitigating w/ time. I'm thinking it may be a symptom rather than cause of the p-stat problem (overheating and pressure escaping at that outlet before the overpressure outlet kicked in).
I had the loxseal in cart at Stefano's and then reconsidered when checkout indicated $9 shipping on the little bottle that costs $28. OTOH, it's kind of silly to worry about $37 on a machine that would cost close to $2k to replace.
I'm planning to wait a couple more weeks and open it up again and take a close look. I can foresee difficulties breaking the connector loose and then dealing with the chuff that gets into the water areas. But if it comes to that, I'll stay away from the loctite's and go with either loxseal or teflon tape.
Thanks again!