Pipe fitting different

Snowmelt

I know I use recently chatted about cast vs Malleable fittings. So I was cleaning out the fitting boxes and I have two same size fittings but different shoulders, can you guys tell me which is which and what’s it used for and why….. not only for me but other heating guys as well…….

STEAM DOCTOR

Cast on the right. Malleable on the left.

Intplm.

The one with the small collar on the left is most often used for gas piping. It is what's called a "malleable" fitting.

It can be used for heating but is a common fitting used for most types of fuel oil and natural gas, as well as LP gas.

The one on the right with the large collar is what is called a "black cast iron fitting". It is commonly used for and was developed a very long time ago for steam heating applications. This fitting is brittle and can be broken apart with a two-hammer method. The malleable fitting will not break apart this way. Hence the term "Malleable".

Snowmelt

thanks steam & int. That’s all I needed to hear unless I missed something. Those two statements where short and two the point

EBEBRATT-Ed

Malleable can be used on any black pipe system, steam, natural gas, LP gas , hot water, chilled water compressed air. etc.

Cast Iron is usually used on steam and hot water. Not allowed on gas. Standard malleable fittings are rated to 150 psi CI to 125lb.

A lot of supply houses only stock malleable.

With the advent of pex, pvc propress and mega press less threaded fitting are used now compared to the old days so the supply houses have cut back on what the stock so some only stock malleable.

CI fittings used to be less expensive don't know about now. CI fittings are thicker so sometimes a larger wrench needs to be used and a wrench with good jaws……wrenches tend to slip on CI.