Radiator leaking below nut & not heating

jgvasa

Today, I noticed the largest radiator on our first floor (living room, near the thermostat) was stone cold. We've been having trouble getting heat on the second floor - a week or so ago, I adjusted the vent rite air vent down to not throw off the thermostat as much. Flash forward, and I discover a puddle of water below the nut where the radiator connects to the valve. A LOT of water. The floor board is nearly rotted out. Additionally, the radiator is stone cold and not getting any heat. Tried tightening the nut thinking it may be loose, but it's already as tight as it will go. Any thoughts?

EdTheHeaterMan

What nut are you talking about?
The nut that tightens the union to a radiator valve?
The packing nut of a radiator valve
The nut on the union to the return or a steam trap on a 2 pipe steam system?
A nut that holds the radiator sections together?

A picture will help.

Since the floor is rotted, this does not sound like something new. It has been happening a wile.

EBEBRATT-Ed

Check the water level in the boiler, is it overfilled?

Check the pitch on the radiator if this is one pipe steam the end with the pipe should be the low end. You can shim the other end up with a crowbar and some shims.

Are you getting heat in the other radiators? If so, make sure the air vent on this one is working (it may have gotten waterlogged),

As far as the leak goes when you have a chance shut the boiler down and take the union on the valve apart. Then slide the radiator over a few inches. You could put sheet metal or pieces of plastic milk bottle under the feet to make it slide easily,

Then clean up both side of the union with a scotch bright pad or something similar (not to aggressive). Then buy a little can of "anti seize" at the big box or auto supply store. Put some on both sides of the union and on the threads and reassemble. If it still leaks you will probably have to change the entire valve and the spud in the radiator

jgvasa

The nut that connects the radiator to the valve. It’s a single pipe system. 

Checked the boiler - it’s not overfilled (half full site glass). Other radiators adjacent are receiving good heat 

jgvasa

jgvasa

EdTheHeaterMan said:

What nut are you talking about? The nut that tightens the union to a radiator valve? The packing nut of a radiator valve The nut on the union to the return or a steam trap on a 2 pipe steam system? A nut that holds the radiator sections together? A picture will help. Since the floor is rotted, this does not sound like something new. It has been happening a wile.

Pictures above. The water drips from where it’s shiny. It’s a single pipe system 

Jamie Hall

That's the union nut that @EBEBRATT-Ed was talking about. They either seal -- or they don't, and if they aren't sealed, cranking on the nut won't help (it may even crack it). Try his suggestions (including Scotchbrite -- never anything harsher). Then, when you go to put it back together, make sure that the two halves of the union (the valve and the spud) are really lined up, horizontally and vertically but also angularly. Unions aren't happy taking up misalignment. If there are no scratches on the mating surfaces, or areas which have rusted or otherwise corroded, it should seal.

EdTheHeaterMan

There is a chance that someone changed out a valve years ago and did not replace the Spud in the radiator. If that is the case, the only fix is a new valve and spud. Try @Jamie Hall's approach and pray for success.