Boiler Question

The supply and return pipes for a hot water boiler with baseboards were steel soldered to copper elbows/fittings. I have never seen this before, the steel pipes sounded exactly like tapping on emt conduit and were very thin. They were rusting and leaking and I obviously wrote it up. My question is has anyone seen this before and was this a product that was once used?




That does not look like steel piping it looks like tarnished pipe with newer 90"s

Ya can not solder copper to steel it is impossible;-)

BTW If you would carry a small magnet in your tool bag you would not have to guess what type of material the piping was made of

It was steel, a magnet stuck to it and look at the rusted section. I agree about not being able to solder it but they somehow did.

With enough flux, solder will flow damned near anywhere. Doesn’t mean it will hold and not leak.

There is a difference between soldering and Brazing its a matter of temp, steel flows at one temp and copper flows at another. Old time refrigerators had steel stub outs on their compressors and we had to braze them.

If your magnet says they are steel so be it but I would write the whole mess up as being dissimilar metals joined together

Good call.

A very odd installation for sure.

Does silfoss work to join steel and copper?

I have only used it for AC refrigeration line joints.

Silfoss is only used for brazing not soldering and the correct flux must be used when trying to braze copper to steel. You can not solder (soft solder) copper to steel has to be brazed only and it does not always hold not many are good at doing that

I understand that and did not use the term solder.

I have both an arc and gas welders Charlie and any number of propane and map gas torches.

I took classes in arc and gas welding many years ago.