Some Radiators not getting hot after replacing all steam traps in the entire building.

SamEnergyPlus

Hi all
I have replaced all steam traps including the f&t traps in a 12 story building this past summer.

Since the heating season has begun, I am getting complaints that some apartments are not getting hot, and when I came back to the building, to check out if the new ste traps are failed closed, I saw that the shut off valves are broken, and it needs to be replaced.
I have even open the union from the steam trap during a heating cycle and there was no steam or water coming out.

The resident from the apartment is saying that she had steam until this year.

Question is there a possibility of having a steam backflow, and the radiators where getting hot until this year from the steam trap side?
Or the new steam trap did in anyway brake the shut off valve?

I would really appreciate if someone can help me out there
Thanks in advance.

Jamie Hall

There certainly is the possibility that with the old broken traps that some radiators were getting heat from backflow through the return. That would not be my first guess, but it's a possibility.

For the misbehaving radiators, are the feed valves really open? There is no way I can think of that something amiss with a trap could damage a valve.

For the radiators which are not heating, does the feed pipe get hot? If not, how far up the riser from the main does heat get?

Do the dry returns get hot? Not just warm, but hot? Anywhere on the system.

How are the vents on the dry returns?

Lots of possibilities...

SamEnergyPlus

Yes the feed pipe gets Hot until the shut off valve. See picture, as stated I have replaced the valve with a new one, and the radiator started getting hot. 
So problem is solved.

My question is why did the resident have heat until this year?

I am working for a company that are repairing/replacing on average 25 thousand steam traps yearly, and so far it's the first time that I am bumping in to such an issue.

mattmia2

Is that a type of valve with a metering adjustment in it? What is that boss to the left of the boss for the stem? There were some steam valves that had an adjustment screw that would meter the amount of steam that was let in to the emitter. With failed traps in the system someone might have opened that up on radiators that weren't heating instead of fixing the steam trap and venting problems and now the system is out of balance.

the system does have a functional way to vent, right?