Leaking hot water radiator piping

Craig Patrizio

I own a 1910 Philly-style home with a gravity conversion hot water system. Runs great. Heats well. I noticed a few wet spots in my basement and traced the water to two separate leaks, both in the vertical piping on the return side of the radiator valve. The leaks are at the thread where the vertical pipe enters the bottom of the valve. One of the vertical pipes may be leaking from below the floor where the rust thinned out the wall.. pinhole, etc.. Any advice on how to crack into the system and rebuild the leaking sections? Any tricks that will help loosen almost 100 years of corrosion so I can remove the bad parts and build fresh? Thank in advance.

Craig

Mike T., Swampeast MO

The radiators connect with unions on both sides. They're brass, so they won't get stuck with corrosion, but don't over-stress by applying too much torque! The union nut side of the valves/unions stay attached to the radiator so turn "up" on the right side of the rad and turn "down" on the left side.

Of course you have to drain the system first

Always use pipe wrenches in pairs! If you don't, you risk either loosening a joint you don't want to loosen, or even breaking/distorting a pipe or fitting.

VERY doubtful that you'll be able to get a full 360° turn on the valve, so you'll need to remove the valve, clean inside/outside threads with a wire brush, then re-make the joint. I'd suggest first wrapping the male thread with 3-4 turns of teflon tape, then put some non-hardening, teflon containing pipe dope over the tape. Then re-tighten.

If you suspect leaks further down the line, you'll have to start disconnecting pipes. Again, rather doubtful that you'll be able to stop the leaks just by tightening an old joint. Better to disconnect and re-make. If the pipes do seem thin, you might as well replace the ones you remove. BE CAREFUL! If the pipe is coming out of the floor you can [usually] remove it with only one wrench on the pipe, but do so at your own risk.

Craig Patrizio

Thank you!

Just wanted to say thank you and let you know that everything went well. After draining the system it was fairly easy to crack the unions on the rads, pull them out and replace/rebuild the leaking valve and connecting piping. Thanks again. Great resource!

Craig

Mike T., Swampeast MO

Glad it Went Well

and that it wasn't a bad problem!