oil-fire hot-water boiler - rust, please advice

[joesat78]

Hi all,
I have a oil-fired hot water boiler w/ baseboard hearing system that I usually keep switched-off during the summer. The same system also provides hot water for domestic needs. I keep the system shut-off during the summer as I don't use hot water during summer. Here is the problem (attached pics) - I noticed the cold water pipe (that server hot water for domestic needs) going into the boiler is getting corroded/rusted. Is there a logic/reason why this happened? The boiler itself seems relatively new. I don't have the complete history of the boiler since I bought this house a little over a year ago only.

1. Can someone tell me why this happened?
2) How to correct this? Is this an easy DIY work or need professionals?
3) how to prevent this from reoccurring.
Image description
image1 - cold water inlet marked in blue, hot water outlet marked as red

 

[jebatty]

The blue-green corrosion on copper/copper pipe/fittings I'm not aware is an issue. This is not uncommon with copper, but others may have different opinions. The exception may be if your water has a pH of less than 7.0, which means it is acidic. You can get some pH paper to test. Water ideally should have pH of 7.0, but for drinking water purposes pH of 6.0-8.5 is considered acceptable, but less than 7.0 can be corrosive to metal pipes.

The rust/corrosion in the blue marked area is different. It appears you have electrical steel conduit in contact with copper. This will cause corrosion by galvanic action. Unless the steel has corroded through or there is a water leak, I would not be concerned. The fix is easy: separate the two so there is no contact. If either is corroded through or there is a water leak, replace the offending pipe and be sure they are separated in the future.

 

[joesat78]

Thank you very much for the valuable information. I'm going to follow the advice here. I hope the corrosion/rust is only from outside and not inside. I remember people saying that you need to run your heater all the time. But, I don't run them at all - only on an as needed basis. I was wondering whether this has caused the rusting. Can anyone confirm?

 

[berlin]

I'd replace the rusted galvanized piece on the bottom w/ brass. Also, w/ threaded fittings of different metal types it's not uncommon for large swings in temperiture - ones like you'd get from turning a boiler completely off, then back on again - to cause some seepage around the threads untill they corrode themselves (or plug w/ small sediment/calcium etc). so yes, it's possible that because of the way you use your boiler, you may be creating some of the seepage and thus corrosion.