Help!

While dissembling a Reneka Viva 1, we broke the drain connector out of the boiler. The brass fitting, formerly attached to the boiler, sheared off in to the compression fitting nut.

Here are two pictures. The first one is of the compression fitting, now with the threads from the fitting inside. The second is of the drain where the threads used to be. The threads on the fitting just broke in the nut.




We're thinking of drilling out the remaining threads, tapping the hole, and inserting a new brass connector like this one: http://us.st12.yimg.com/us.st.yimg.com/...51_7853283

We'll solder the new connector in to our newly tapped hole. (Lead free solder)

Any thoughts or suggestions or warnings with this plan? What are some other options? One concern we have is that we won't get many threads in the remaining brass on the boiler (it'll be just the thickness of the boiler, and the hex nut you can see in the second picture).

Another option may be to NOT tap the hole after we drill out the remaining threads, and use another nut on the inside of the boiler.

I would apply some heat to the nut and "loctite type" material surrounding same and see if you can remove everything from the boiler shell. Clean the surrounding area inside and out and solder on a boss tapped with the threads of your choosing.

I'd also install a small ball valve in your new line to facilitate draining/cleaning.

I like your drilling and tapping idea, but forget the soldering, to solder on a copper boiler you would need an enormous blowpipe to get the required temperature.
If you have a blowpipe you could try @erics idea.

My idea would be to start with cleaning up the broken fitting with a grinder, then increase the existing hole large enough to allow you to tap a new thread for a new and smaller size connection, the new fitting would need to have a tapered N.P.T thread, all you would need then to get a good seal is Teflon tape.

With the new smaller drain fitting you may have to also modify the connecting pipe size, this should not be a real problem.

I have dealt with a number of stuck parts dealing with cars and motorcycles over the years. You should have seen what it took to get the fill bolt of my Volvo's tranny since some idiot over-torqued it while it was hot...

Anyway, without being able to look at it (if you have a link to a picture of the part, that would be of great assistance), and basing the following advice on that photograph from you , here's what I would do, assuming that the broken fitting on the boiler threads into the boiler and it not brazed in or in any other way permanently attached:

1 - Try a quality penetrating oil. This assumes that the boiler is going to be cleaned thoroughly afterwards, and that the heating element is already removed. I wouldn't want that stuff on the element.

2a - Heat and cold are good allies in a case like this. Slowly heat the area with a small (propane) torch, and using a small hammer continually and LIGHTLY tap on the fitting while heating. We use to be able to free the nuts on corroded battery hold downs with that method, just using very hot water.

2b - If 2a didn't work, after heating, and while still hot, apply a chilling spray (or ice, or dry ice) just to the fitting and not the boiler. Then immediately try to tighten (just a tiny amount) and then loosen the fitting. If that doesn't work, repeat 1 and 2 again.

3 - That fitting is held in place, not only by the sealant and possible corrosion, but also by the stretching of the threads. A lot of that force is against the head of the fitting against the boiler's surface. As it was tightened originally, the head stopped moving towards the boiler's surface, but the threaded portion kept turning. This places the threads under tension. Removing the head (the exposed hex end) of the fitting will release a lot of that tension. After that, using a reverse tap may back out the remaining portion of the fitting still in the opening.

4 - Worst case, since it is just a drain, you could have another threaded insert brazed into place.