Name this fitting

angelotrivelli · October 20

I've got an AGA gas cooktop that has a slight gas leak. Using a flammable gas detector, I isolated the source to one fitting.

The fitting looks like some type of flared fitting. It had a stiff washer in it too. Before I try tightening it up again, I would like to know more about it. This is a British-made cooktop.

I am not sure exactly how the washer that was in it is supposed to function. It does not seem supple enough to form a seal, so maybe it sits on the back of the upper nut (not shown) to prevent galling as the nut is tightened?

Here's a pic…

BTW, here's the washer. It's not 100% obvious to me what role it has.

PC7060 · October 20

Looks like a typical union fitting. The mating female that captures the flare is the part you described as off camera. Your guess on purpose of the washer sounds reasonable.

Edit: thanks for update pictures on gasket. Per @hot_rod - that gasket seals the union.

angelotrivelli · October 20

Thanks! That helps me a lot!

I notice there's some discoloration on the part that seals. I wonder if that's some kind of contamination. These types of couplings are supposed to be strictly metal-on-metal, right?

I am tempted to try cleaning it off. Perhaps removing the corrosion on the outside upper pipe with steel wool, and using isopropyl on the mating surface.