Old cast iron radiator leaking at pipe, can't shut valve because that leaks too.

jtor1134

So I just bought an old house with a steam heating system, which I'm new at (but learning!). Anyway there's one really old cast iron beauty that's been covered up by one of those fancy wood housings. I just noticed that it appears to have been leaking for some time right at the gigantic nut where it attaches to the valve. It spits out of the bottom at random intervals so temporarily I put a little metal bowl underneath it to catch the drips. It seems to have leaked about a good ounce or so over a 10 hour period and you can tell this has been happening for a while since the wood floor underneath is warped to all hell. So this needs to be fixed.

See this pic. I circled where the water is dripping from.



I don't think this bad-boy is going anywhere anytime soon so I was just going to JB weld around the fitting but I would obviously need to close the valve to keep the radiator cool for at least 24 hours. Well low and behold, once I started to close the ancient valve, it too started leaking around the shaft and continued to do so even when fully closed. So that obviously wont do. Pic attached for reference.




So next question is what do I do? I'm hardly a plumber but I do know which end of a wrench to hold (auto mechanic). Is the valve easily replaceable? The age of the thing is what concerns me. Do I need maybe just to tighten things? I'll obviously need to get a GIGANTIC wrench, but that's fine. Harbor Freight is nearby.

unclejohn

Turn the nut in the red circle clockwise that should stop that leak at the stem. I would leave the bowl were it is until spring and deal with it then. I would not use the JB weld.

Fred

There is packing under that nut around the valve stem. You may be able to tighten that just a little to stop that leak. If not, take the nut off and buy some packing at the plumbing house and repack it.
The large union not may just need to be tightened as well.

JUGHNE

On those packing nuts, I turn the valve about half off to where it seem easier to rotate. Then snug up the nut just a little. If you get 1/4 to 1/2 turn that might do it. Then open up, if the leak has slowed down just leave it. As the old packing gets wet it will swell and tighten things up. You do not want to crack the bonnet nut by to much torque, it is old brass.

The large union nut appears to have a hard life. I too suggest leaving it until spring. Then a 14 to 18" pipe wrench might seal it. Those are a fine thread and can strip out or crack. Not what you want right not.

If the nut cracks or will not seal then you may have to replace the entire valve.......come back here in the spring.

In the meantime there are some good books to study.
"We Have Steam Heat" is a good interesting read.
Check what pressure your boiler runs at.

jtor1134

Well the valve only leaks when I try and turn it off. Fully opened it's ok. I agree now that it probably needs to be replaced but for now I can leave it. The leak at the union nut worries me more since emptying the water bowl will become a daily chore but I'll figure out a way to live with it. Breaking something right now is the last thing I want to do with outside temps being what they are.

I plan on making a separate post going over my entire heating system because I want to learn everything about it, including the pressure, the various valves etc... Here is a pic of my pressuretrol though set as I found it.

nicholas bonham-carter

You can try to tighten the main union nut, while rocking the radiator a little. An eighth turn may be enough.
The valve can be repaired in the spring-directions here.—NBC

Jamie Hall

nicholas bonham-carter said:

You can try to tighten the main union nut, while rocking the radiator a little. An eighth turn may be enough.
The valve can be repaired in the spring-directions here.—NBC

^this. Very often works.

BobC

All these suggestions are good but you are dealing with very old fittings. If it is as cold where you are as here I would try and limp through to more seasonable weather before doing something that may go sideways.

Bob

jtor1134

The issue is that it leaks so much that I need to empty the bowl every 6 hours. I decided to take a shot at re-packing the valve, and it seems I was successful. I decided then to go with something a little less permanent than JB Weld and used RTV silicone on the union nut, leaving it to dry for a couple of hours. It stopped the leak there but the water seems to be coming out of the back side of the union nut now, but in smaller quantities. I might try sealing that side too but if that fails I'm going to take a stab at tightening the union nut, but not until after this cold snap ends.

nicholas bonham-carter

Take the union apart, and look carefully at the nut, (for a crack), and the mating faces. Use a Scotchbrite pad to make them clean. Lubricate the faces with dishwashing liquid, which unlike pipe dope, JB weld, and other things some people may use, has no solid in its makeup to keep the mating faces from sealing, and align the faces.
When starting to tighten up the union nut, turn backwards so you know when the nut threads have dropped into alignment with the spud threads, and finger tighten. Finally use the Channelocks to tighten further while rocking the radiator side to side. If it looks like the radiator needs to move closer to the valve, use a lever to help it.
Unions will have no problem making a watertight seal if they are properly aligned with clean, undamaged faces.—NBC