Pump Corrosion

[Antifed]

Hello,

I was on a site visit the other day and came across this Armstrong Pump in the secondary side of a heating hot water system. There are no corrosive chemicals in the room nor anything outside of the boiler room that could be drawn in from the combustion air louvers. The maintenance folks say that this is happening in multiple locations on the campus and in both the chilled water and heating hot water systems. Both the heating water and the chilled water have chemical injection systems. To my surprise, this pump was still running. There was no discernible leak. My supervisor thought that it may have been caused by a very small leak and stray currents. The only time that I have seen a pump and piping this badly corroded was in the pump room for a natatorium where the end-user kept the lid off of the chlorine tank.

Would you all be able to provide some ideas as to what could be causing the corrosion?

Thanks!

 

[TBP]

Pump seal/packing leak. I see that as the only way to explain the corrosion extending to the top hole in the coupling guard and the small diameter piping - it was sprayed there by a running pump. Corrosion this extensive didn't happen from one day to the next - doesn't look like the operations/maintenance people are checking the equipment on any kind of regular basis, for whatever reason.

 

[3DDave]

What is the small massively corroded pipe on the right side of the image for?

 

[LittleInch]

So the obvious question is what is the "chemical".

Have they injected too much?

Or not enough?

Have they done any water sampling or analysis or just sat around having coffee going "There's another leak on a set of pumps, I don't why, but it means we have more work so let it sit there until someone asks...."

But looks like whatever it is is eating your seals. What are your seals and what is the chemical is the first compatibility question.

 

[TBP]

I'm not convinced that this is necessarily a chemical attack issue. I've seen external corrosion like that on uninsulated cold water pumps that were located in a humid area. Could have been something like a leaky fitting where the seal flush connects to the pump. Any minor leakage like that should have been drained away by the small diameter copper piping on the right of the picture, but I doubt that it functions very well, as it looks like it's piped some distance to - probably - a floor drain. I believe that pump in the background of the picture is the sister unit, and you can see the copper drain line run along the floor. I imagine that the drain from the pump with the corrosion issue ties into that line. I've never liked that piping arrangement - you can't easily tell when there's a problem, because there's no water on the floor to indicate it. That long copper drain line is probably plugged with flakes of rust & debris from the outer pump housing anyway.