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[allis48]

Inside of the one end is all pitted and the other end looks fine. This is only two years old going on third season. Bad fitting otr something else causing this?

[slimjim]

I'm going to bet there was a pocket of air at that fitting that never got removed.

[Scott7m]

Are you using a broeder 3 speed?  What is length of run

Ive heard to much flow can pit and wear fittings but never seen it first hand

[allis48]

I was running the broeder 3 speed for the first two pumps i was running them on middle speed but now it has a  bell and gossett pl36. Its is a 30 foot run but its about 10 feet above ground cause it a hanging wall heater.

[allis48]

Hey Guys I still need help here with these fittings. I had to change 3 of them this season and this one was already changed around thanksgiving. What is the problem/s? Is there anyother fitting that I can use that will hold up better?

[slimjim]

I think you will find that air elimination is going to be the key, I would bet the deteriorated portion of the fitting is on the outbound side am I right?

[allis48]

I can't remember which way it was this is the other end of same fitting not as bad but still started. This one (changed twice this season) is on inlet side of heat exchanger the other one I chnged this year was on outlet side of same exchanger.Do you think I should replace it with a tee ans short peice of pex and ball valve to bleed off air?

[slimjim]

When you say heat exchanger, water to water or water to air? what I'm looking for,  is that fitting in the pressurized or non pressurized side of the system, it will be impossible to eliminate air in the non pressurized side but air elimination on the pressurized side is easy, resistance in those 90's are way up there can you eliminate some of them or use long radius 90's

[Sprinter]

How does air erode brass?  There is a known problem called zinc depletion from chloride levels in some brass pex fittings, but I don't think this is the case in a boiler.  The zinc problem usually has lots of crusty build up that's blue ish white. That brass surface looks like erosion? Any  copper in the system other than Air handler.

[allis48]

This is what I m working on the red line I changed twice this season the blue once. It is none pressurized. I have a total of two elbows on this loop both in this picture. I have a total of 6 on house loop haven't changed any of them yet.

[Sprinter]

So you've gone thru 2 pumps and on a third?  Does the pl36 only serve the 30' pex and air handler? If that's all it is in the loop, there's probably no temp diff in S&R lines with water flowing 50mph.
Can you hear the water flowing in the pipe

[LittleJohn]

What kind of GPM you running thru the fittings, cause you should try and keep water velocities below 8ft/s ( or you get this little thing called erosion)  which maybe what you are seeing.  It woudl be very interesting if you also knew which way the water was flowing thru the fitting might lead you down the path to an answer.

[allis48]

By looking back out some of my other pics from before it it the outlet side of the fittings that is the worse. I have about 15 degree drop from one side to the other

[CRJR]

Do a Google search for "dezincification"

[Sprinter]

I think that was an older problem, even the lawsuits are over. But its possible he has some very old stock. The zinc problem was more of a pitting and lots of whitish blueish calcium looking buildup. You'd find it mostly on the ribs where the crimp seals. You would have a nice size pin hole in the elbow or leaks at the ribs.