Newer single-pipe steam radiator not heating this season

SRandazzo87

I have a gas one-pipe steam heat system in Westchester County, NY. The system has always worked well and all my radiators get hot fast.

Last year I had a new recessed radiator installed when redoing our kitchen, which is on the first floor of our house (directly above the basement). The plumber connected to the existing steam system pipes in the basement which are either black steel or cast iron (sorry not sure). He transitioned from cast iron to copper for the new radiator, then back to black pipe/cast iron when connecting to the radiator (pictured). The length of copper run during the transition is about 6-7 feet, and the copper is not insulated (the rest of the black pipe is).

This new radiator worked great last year, nice and hot, but so far this season it mostly cold. After hours of heating it will get a little warm, but never gets anywhere as hot as the rest of the system. Even radiators that are farther along in the system got nice and hot, but this one does not. We have another radiator in the system that was added the same way - with copper pipe, and is on the second floor, and that one gets nice and hot.

I suspect some amount of heat loss from the copper, but not enough to cause the radiator to be cold. Like I said, the other radiator with uninsulated copper gets super hot without any issue, and is even further away from from the boiler than this one.

Is it possible the recessed radiator has a blockage? Rust maybe?

See pictures below, thanks in advance!

EDIT: I want to add that when the system is running, I can hear/feel a small amount of cool air coming from the small vent on the kitchen radiator. So some amount of air is escaping through this radiator/vent, yet still it's cold to the touch. I have also ensured the radiator valve is in the open position.

EBEBRATT-Ed

With the boiler shut down remove the air vents one on the supply pipe and the ones on the radiator . See if you can blow air through them. You can soak them in vinegar & water mixture. Since the rads worked befor they should work now.

jesmed1

https://forum.heatinghelp.com/discussion/76169/steam-radiator-vents-maintaining-and-or-replacing

bburd

The radiator runout should come off the top of the steam main at a 45° angle (approximately) and should pitch back toward the steam main so condensate can drain back to the boiler. Check it with a level. Pools of standing water will block the steam.

ethicalpaul

Two great suggestions by @EBEBRATT-Ed and @bburd but I'd lean toward Ed's because it wouldn't have worked well last year probably if it was a pipe pitch problem.

BobC

I have a similar setup with that same radiator in my bathroom which is on the second floor. A copper run out comes off the 2" steel main and runs across the cellar and then turns up the outside wall. it's about 20ft of copper. That wok was done about 45 years ago and that little radiator just pours heat into that bathroom.

If the radiator vent is working I think you have a pipe pitch problem. If there is a run of pipe that is pitched wrong it can slowly collect water and condense any steam trying to cross it so it just does not get to that radiator.

Use a level and check that pipe along it's length to see if it has pitch all the way back to the boiler. You may have to stretch some string along a run of copper to see if there is a belly that can collect water. You need proper pitch so water can find it's way back to the boiler.

Bob

SRandazzo87

Thank you all for the replies, this has been a learning experience for sure.

Here is what I've done since reading all your posts:

- Checked with a level that the pipe slopes away from the radiator. It most definitely does, i can tell just by eye that's it's very sloped away, but verified with a level anyway.

- Removed the vent, soaked in a vinegar/water solution. Did this multiple times and a good amount of rust exited the vent as I shook out the solution. did this multiple times, and was able to verify I could blow air through it.

Since doing this, the problem persists. Only a small portion of the left side of the radiator get's warm, but not hot. I am wondering if I need to remove the radiator and clean out the insides?

EBEBRATT-Ed

When the boiler comes on for a call for heat and it starts steaming check the vents to see if they are venting air.

If the rad worked before it should work now

SRandazzo87

EBEBRATT-Ed said:

When the boiler comes on for a call for heat and it starts steaming check the vents to see if they are venting air.

If the rad worked before it should work now

Just kicked on the heat and hung out by the radiator for a bit. I can indeed hear a steady stream of air coming out of the vent on the radiator in question. Waited long enough so that all other radiators are piping hot, but this one remains only slightly warm on one side with air continuing to escape from the vent at a steady pace.