Rust on reinforcing band INSIDE Pentair CC420

[W.J.Christy]

I opened the filter today to clean the cartridges and found the steel band around the top of the filter to be rusting and leaving stains down the sides of the filter bottom. Is this normal? I maintain my chemistry to be in the acceptable ranges but still got the rust.

Any insight is appreciated.

 

[Jimrahbe]

WJ,

You and everyone else... This has been reported many times before and it is not a problem with your chemistry. It is a problem with how Pentair processed the band during manufacture. It is not as bad a problem as it looks. It is more a visual issue and nothing is going to rot away.

I just clean it up when I clean my filter, twice a year.

Thanks,

Jim R.

 

[JoyfulNoise]

It’s “normal” in the sense that it’s common on Pentair filters with the internal steel band. It’s a consequence of the manufacturing process used to make the band as you typically see rust around the tack welds.

You can use Bar Keepers Friend liquid cleanser to clean all the rust stains off but they will come back. Just be sure the rinse the filter really well after using BKF.

 

[JamesW]

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[W.J.Christy]

I feel better now. I am glad that it's not something I did.

I appreciate all the input!

 

[JamesW]

In my opinion, they start with good stainless steel and then damage certain parts as they heat and bend the steel causing defects in the steel that are susceptible to corrosion.

 

[W.J.Christy]

Most likely the spot welds sensitized and imparted a good bit of stress on the stainless steel making it very susceptible to chloride stress corrosion cracking.

Oh well as long as there isn't a history of failure even with the corrosion I am happy.

 

[JoyfulNoise]

Most likely the spot welds sensitized and imparted a good bit of stress on the stainless steel making it very susceptible to chloride stress corrosion cracking.

Oh well as long as there isn't a history of failure even with the corrosion I am happy.

I have a 10 year old QuadDE filter which is basically the same thing as the C&C, just different guts. The same corrosion shows up on the strap. Hasn’t failed yet … knock on wood …