Extension radiators don't get as hot as the rest of the building

MynameisHope

I have a Brownstone building located in Brooklyn, NY, built in 1912, which has a 1-room extension on the bottom 3 floors of the building. I believe the extension was built at the same time as the rest of the building and turns the building from a rectangle shape to an L shape in the back. The building is 4 floors and has a gas boiler and steam heat which goes up through risers and radiators. The rooms on all three floors of the extension are consistently about 5 degrees colder than the rest of the building. Sometimes the risers are hot but the radiators don't get hot at all or get only a few rungs hot, where as the radiator in the main part of the building on the same floor is super hot. On really cold days when the heat is consistently pumping, the radiators in the extension will get warmer than on less cold days where the heat goes on and off. I've changed out the windows, put in a new radiator and nothing seems to help.

Any advice on this issue would be greatly appreciated!

Thank you

mattmia2

Is this 1 or 2 pipe steam? You have to balance the system, how you do that depends on what type of system it is (or there could be more serious issues like a sagged pipe trapping water).

MynameisHope

@mattmia2 thank you for your response. I'm not sure if it's a 1 or 2 pipe system. The system is from 1912 and I don't believe it's every been changed. It has risers that go into the radiator on the left side, on the right side there is no pipe that goes back into the floor. So there is only 1 point of access in the radiator. Would you mind telling me how I can figure out if it's one or two pipe system?

ethicalpaul

If there's a single pipe going into each radiator, it's a one-pipe system. Do you see a vent (probably chrome-colored metal) attached to the side of the radiators opposite the pipe?

MynameisHope

Thank you for explaining. Yes we have a vent on each radiator. I've switched those out to have the largest hole possible in the rooms with issues, but it's still not fixing the problem.

KC_Jones

What is the main venting like in the basement?

You shouldn't need big vents on many, if any radiators, as all they should be doing is venting the radiator and the runout to said radiator.

Balance starts in the basement with the main venting, until that's correct you will have a very tough time balancing the rest.

ethicalpaul

MynameisHope said:

Thank you for explaining. Yes we have a vent on each radiator. I've switched those out to have the largest hole possible in the rooms with issues, but it's still not fixing the problem.

This does not surprise me, but it was a good first thing to try, being inexpensive and easy.

I will bet anyone $100 that in this extension there is a pitch problem or sag in the supply pipe where condensed steam (water) is pooling. At every call for heat, this pool of warm or cool water will kill a lot of steam.

If the pool is high enough that it completely blocks the pipe (again, due to a sag or outright downturn in the pipe) then it will take a very long call for heat for that water to get heated up almost to the temperature of steam to allow some steam to pass (often with some gurgling sounds). There may also be some banging or pinging, but not always.

Sometimes the pipes just sag from settling, but since this was an addition, I would bet another $100 that the people who installed it know nothing about steam and more or less purposely installed the pipe in this manner (with a low spot).

The only solution if this is the problem is to get access to this pipe and modify or re-run it so that all condensed steam is able to drain from the pipe back to the main.

Check what @KC_Jones wrote above about the main venting, but if that's OK and the problem persists, start looking for a pipe drainage problem.

MynameisHope

Thank you all for the comments. This is really helpful. I called a boiler person who just came and tuned up the boiler. Could any of you recommend who I should call to deal with the issues and suggestions you all raised? Is it a plumber instead of a boiler company? Or some kind of specialized person? I'm in Brooklyn, NY - if anyone has any recommendations or experience with anyone there I'd love to hear it.

STEAM DOCTOR

I would tend to agree with Paul. In all likelihood the piping to the extension was not done correctly. Do you know when the extension was done? Bear in mind that the fixes could be expensive and painful. There are many ways to pipe incorrectly. Not that many ways to pipe correctly. Could be a sizing problem or a slope problem etc etc. Maybe the pipes are running through a cold crawl space. Who knows. Without opening walls and things like that, might be no way to figure it out. But obviously no way to know without eyes on site. There are plenty of highly qualified steam experts on the site who service Brooklyn

STEAM DOCTOR

Is there any banging in the extension radiators? You might want to speed up the venting on the mains and slow down the venting on the radiators in the non extension part of the house

EBEBRATT-Ed

@MynameisHope

I would send @JohnNY a private message. he would be your guy.

mattmia2

There are a couple others besides @JohnNY in the area too but I don't know who does NYC and who is only other parts or NY or NJ but John knows his stuff.