Pipe rust, possible to fix myself?


Old 06-08-19, 08:25 PM
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Pipe rust + leak, possible to fix myself?


Trying to figure out if this is fixable myself. I have a Weil-Mclain boiler.
Already replaced the expansion tank, changed out the circulator for the water.
Replace the psi gauge with a new one.
The only problem now is that I'm seeing water slowly leaking from this section. Is this fixable? I've already turn off the water line and the boiler.
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Old 06-08-19, 11:54 PM
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Some type of union?

Guessing the only way that is going to be fixed is by cutting off and replacing.
Old 06-09-19, 04:53 AM
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It all depends on what type of connection the bottom half of the union has. If it is threaded, you will have to drain that piping or the whole system unless that section can be isolated, break the union, unscrew the bottom half, cut the copper above , and replace the removed parts with new. The union is copper by pipe, and the reducing fitting above it is a female by fitting, (can not tell the size from the picture). If the bottom half of the union is a copper sweat connection, , which I doubt it is, then I would call a plumber of HVAC company for help. If you are not good with soldering or fixing piping then I would opt for help. The simple repair may turn out to not be so simple.
Old 06-09-19, 05:49 AM
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Should be a dielectric union. That happens from electrolysis from dissimilar metals.
It’s likely a sweat connection on both sides with an NPT nipple going into the boiler under the sheet metal cabinet. But could be sweat to NPT.
Old 06-09-19, 03:14 PM
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The leak started first, which then caused the corrosion. The leak should have been fixed as soon as it was barely noticeable. This is going to be a bear, I fear. I pride myself in being an advanced amateur plumber, but I would call a pro. Inspect your entire system, see if there are other leaks - if so, get them all fixed.

The air eliminator in the photo has seen better days. It all points to a long-term lack of routine maintenance.
Old 06-09-19, 03:37 PM
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House is 30 yrs old. We took over the house 10 yrs ago. We turned off the system 4 years ago due to a circulator leak. I just fixed the circulator this year and decided to get the system running again. Not sure how to fix this issue.

I'm guessing this requires pipe cutting? soldering? and some other stuff? Can't be repaired via some sort of sealant right? Should I drain the entire system now to prevent the water form eating through the rust?
Old 06-09-19, 04:28 PM
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Nope..... no easy to apply sealant is going to help. Replacement is needed.
The damage is done. Turning the water off isn't going to help much unless you get water leaking.
Old 06-09-19, 04:41 PM
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Nothing can be done other then replacing the entire fitting. Soldering, pipe wrenches and other plumbing tools will be involved.
You’ll also have to drain the system down to below where this fitting is, then refill and bleed once complete.
Like I said previously that should be a dielectric fitting. If it isn’t the leak, and rot, will return.

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