Steam input seems to be block ways to unblock?

Ed. W.

Two pipe building, four stories tall, third-floor bath rad no steam out of supply, Replaced Trap, Removed supply shutoff valve, valve full open. All other floors' bath rads are functioning correctly. I am thinking of air pressure on the supply to unblock possibly; any Idea would be helpful. Thanks, Ed. W

Mad Dog_2

Any Pictures Eddie?  Mad Dog 🐕 

Ed. W.

Sorry, there are no pictures, The Tenant refuses photos.

dabrakeman

Is there any horizontal section of pipe below that radiator that could be pitched wrong and trapping water?

Jamie Hall

Try pouring water into the both the supply piping and the return piping. It should flow freely through both. A problem in either supply or return could block the heat from that radiator.

STEAM DOCTOR

Ed. W. said:

Sorry, there are no pictures, The Tenant refuses photos.

Okay. No pictures equals no heat. You don't have to take a picture of the tenants in the bathroom. Just a picture of the radiator and piping.

STEAM DOCTOR

And what's the history? Did this ever work? Any changes made?

Ed. W.

There is a straight supply into the radiator. I cannot see under the floor. Hiislory has functioned correctly. Water in supply is an idea I will try. Putting a 1/2 inch pipe adapter to my pressure unit to the supply line might unblock. I will do that first. I do not wish to open the ceiling in the tenant below. My guess is the riser tap to the radiator is blocked with debris; what about a thin snake?

Mustangman

If you don't have steam at the supply valve, with the valve disconnected or off, the problem is in the branch piping between the main and the radiator. Radiator valves have a stem. Sometimes the stem breaks which renders the valve useless, regardless how many times you turn the handle. You can disassemble the valve at the bonnet and check for dirt. When taking the valve apart, Always keep anjusting the stem thru the process so it feels free. If you don't, you can jam the valve and strip the stem threads. Loosen the bonnet assembly, the bigger octagon nut on the valve. ( Not the packing nut which seals the valve stem.) As you are unscrewing the bonnet go counter clockwise with the valve stem and handle until the whole stem assembly comes apart. Turn on the heat and see if you get steam. If you don't have steam coming thru the disassembled valve, there is a blockage in the branch piping on the supply side. You could use compressed air to try to clear it. WIth the system off, adapt your air compressor to just the supply piping. ( May have to remove valve and connect to the threaded supply branch.) If you blow it down, toward the main, all the black stuff will blow into the main and not all over the walls and floors if you tried pumping from the basement up. After you establish that the branch is open, re-assemble and fire it up. Thats where I would start. Over the years I have had this issue more than a few times and many times it is the valve. What kind of steam vent is on this system in the basement? Radiator vent?
Good luck Ed

Ed. W.

Mustangman,
I removed the input valve, and it is functioning properly. As I indicated, I guess that the branch off the riser is blocked with debris. Since it is a 1/2-inch supply, I figure air pressure, water, or snake to unblock. Steam trap vent, Barnes and Jones cage unit 3472 for a sterling 1/2 trap.

Jamie Hall

Half inch? Pretty small. But don't forget the return! Work on the supply, yes, but work on the return, too -- if you find you get steam in the supply, but still not heat, check the return. If the air can't get out of the radiator, the steam can't get in (now who said that?).

Ed. W.

Main steam vents multiple Hoffman 75's, Removed both supply valve and trap, pressured the system no steam in supply no steam from trap side.

Jamie Hall

Well, at least there's no steam from the return side... now assuming that water can flow down it, that's one headache out of the way. No steam on the supply side, though... somewhere there is a block, but it needn't be debris. It could be a low spot in the piping trapping water, and the steam pressure isn't enough to get past it (but don't increase the steam pressure to compensate!).

Ed. W.

I plan to put air pressure into the supply side to blow debris out of the way, probably in a few days. I have to modify my pressure device to fit 1/2 inch NPT.

STEAM DOCTOR

Really hard for me to believe that there is debris in a steam Supply pipe. This is that a drain pipe we're talking about. Water maybe. Even that does not seem so likely. One day it's functioning perfectly and then the next day, without any banging, there is no steam to talk about. I think that we are missing part of the story here. And if there is debris and you try to pressurize it or snake it, then it's your fault if that debris ends up somewhere else. Was there any construction done anywhere in the building? Are there valves elsewhere that may have been shut off? Any possibilities someone cut the pipes in capped them?

EBEBRATT-Ed

Something is probably disconnected

Ed. W.

There has been no construction in the building, My guess is corrosion in the pipes which may have fallen off and blocked the tap of the riser feeding the radiator.