Steam Radiator steam valve leaking from underneath stripped capping nut.

718KW

The radiator is leaking at the point of the capping nut and piston meet. The piston handle is frozen onto the piston handle, but fortunately I can work around that as I can lift the capping nut about two inches until it is stopped from removal by the handle. I followed the instructions on the second part of the video below made by this old house. I basically wound graphite packing string around the piston and then tightened the capping nut. It helped a great deal but it felt like the thread on either the capping nut or the valve was stripped. In other words as soon as the nut appeared be tight the nut slightly slipped. I put downward pressure on the nut and got it a little tighter, but don't want to over tighten as the nut will just slip. As a result of the graphite string and getting a bit more tightness on the nut the valve stopped dripping but you can see moisture trying to bubble up from under the cap onto the piston. The water does not leak down the valve so I have had some success. Is there any way other than changing the valve (a challenging and possibly successful project, or a completer failure if I mess up) to ensure absolutely no water. I see how it is done using a sawzall and chisel in three different places).

BobC

Try wrapping some teflon tape around the thread (4 or 5 turns) to see if that will allow you to tighten up that nut more.

Bob

ww

hopefully that teflon tape idea works and maybe use some pipe dope or paint on threads as well as the packing in the stem if it didn't...or all three methods.

it's possible that the nut is cracked..if it is...get a small hose clamp or tighten some wire around where the packing nut is..and see what happens...also loosen the nut again..put less of the graphite packing..maybe put some pipe dope on the graphite piece and put it back. find out what actually is stripped...do you have some photos?

hopefully it worked out...if not you'll have to remove the big union nut at radiator. then use two pipe wrenches to remove valve. now if you get the same brand valve and the side of the union that connects to the radiator is the same then you can just put the valve back..and maybe it will fit anyway..

but if not you'll need a spud wrench to get the part off on the radiator and install the new one. nothing is easy but if you know how to do it it's alot easier...or have mechanical aptitude.

don't forget..this is steam..if you run into trouble..just cap the pipe off and think on parts,etc...you can still use the system.

Mark N

Could you please post a picture of the valve. I replaced all my rad valves and spuds this past summer after having my rad refinished and it was no big deal. Al the spuds were in bushings and the bushings came right out of the rads. I used 1 pipe wrench to hold back on the supply pipes and another on the valves. I was able to remove them all. The valves were brass so therefore did not rust to the pipes.