Radiator Breathing

Kjmass1

I have 1 large radiator, that is the furthest from the boiler, that needs a C/D sized vent (1 pipe system) to heat the room and get the steam there quickly. The main pipe seems to vent properly and quickly (2 Gorton #1s).

This radiator vent makes very loud breathing/panting/inhaling sounds in between venting air out. Sometimes sounds of gurgling water. No water hammer. Radiator is more than pitched enough to drain. What's causing the inhaling?

This is on an old addition, so if the boiler to the end of main and main vents is 25', the branch to the troubled radiator is another 15-20' beyond that.

Fred

It sounds line there is water laying /pooled in the horizontal pipe that feeds that radiator. While you have the radiator pitched, you also need to check the run-out that feeds it (in the basement or crawl space and see if it is pitched back towards the Main or if the pipe has a sag in it.

David Nadle

The panting is because the steam is slowly heating the mains, takeoff, and radiator. There's a progressive cycle of steam advancement and condensation causing a pressure and vacuum cycle. If you increase the main venting and reduce the radiator venting, that should greatly reduce the effect. If the radiator needs a D it's probably because the other radiators are vented too fast and the mains is vented too slow.

Kjmass1

Thanks. My long main has 2 #2's, and the shorter main which this one is on only has 2 #1's. I'll look in to adding another #2 to that line and see if I can slow down the venting to that rad.

BobC

Make sure that main and the pipe connecting the radiator to the main has adequate slope and there are no dips along the pipes.

Bob

Hap_Hazzard

Panting is caused by a kind of low-energy water hammer. Water lying in a part of the system usually unrelated to the panting radiator prevents air from passing, forcing the air to escape from vents in other parts of the system. As it does so, the pressure gradually builds up, as the available venting restricts the air from freely flowing. The buildup of pressure gently pushes the slug of water along until it reaches a point at which the air can escape past it. Sometimes this occurs near a drip or return, where some of the water abruptly drops into the return. While the pipe is temporarily free of water, the accumulated pressure rushes into the parts of the system that were previously inaccessible and air flow through the vents that were breathing drops off, until the water pools again and the cycle continues.

The reason the panting is most noticeable in the radiator you identified is probably simply because it has a C or D vent. More airflow means more noise. Walk around and listen to your other radiators when the house is quiet and this panting is happening. I bet you'll hear it in several of them, and if you make a note of which ones are panting in unison, you'll start to narrow down exactly where the water is pooling.

Also walk around the basement and listen for water running down the drips and/or returns in intermittent torrents during the same part of the cycle. If you can hear it it might provide another clue.

Another clue is that a pipe full of water will stay warm longer. If you have a non-contact thermometer (or better yet an IR camera) you can sometimes spot sections that stay warm longer than others, even through a wall.

nicholas bonham-carter

I think the panting must come from water in a low spot, sloshing back and forth, in the line leading to the problem radiator. At the end of the line, the pipe would be smaller, and more able to be occluded by water. Can you put some upward pressure on that section of pipe, to see if there is any difference?--NBC

Kjmass1

Thank you all for the suggestions. I do believe there is the possibility of a flat pitched pipe in this section...it's partially hidden in the ceiling and pretty locked in there. I'll have to do a little investigating to see if I can get it to move a little bit.

Captain Who

Any flat sections or dips could also have accumulated sediments over the years, which effectively reduces the diameter of the pipe. Definitely not good in a counterflow situation. Flushing can help in those situations, but you need to do it in a way where it doesn't flush crud back into your boiler.

bvaughn76

I am having a similar issue. The water in the pipe sounds like ocean waves rolling back and forth. I had everything quiet in my one-pipe steam system and then my low water cutoff failed and I cracked the top of my boiler. The boiler was swapped out and now I have this breathing and sloshing water happening. Any thoughts on what the boiler change did to cause this?

KC_Jones

bvaughn76 said:

I am having a similar issue. The water in the pipe sounds like ocean waves rolling back and forth. I had everything quiet in my one-pipe steam system and then my low water cutoff failed and I cracked the top of my boiler. The boiler was swapped out and now I have this breathing and sloshing water happening. Any thoughts on what the boiler change did to cause this?

Did they skim it after install? Did they install it correctly? I would suggest starting a new topic if you are having troubles, don't want to get lost in this one nor hijack someone's thread. Start a new post with your specific questions and pics of the new install would help as well. Pictures are very helpful.

bvaughn76

Thanks, just thought about moving this to my own thread. Will get some pics too.

BobC

When the new boiler was installed they may have changed the height of the main a little bit when connecting to it. The slope may have been ok before but now is marginal.

Bob

Kjmass1

So I was able to adjust the slope of the hidden pipe by about 1/2". I heard some water drain down so that was good. I think the breathing has lessened, but I might have traded that for a little bit of water hammer. I'll keep an eye on it. Thanks.

Kevin

nicholas bonham-carter

Sometimes raising the whole radiator (extra quarters under each leg) will correct a wrongly sloped pipe underneath. A small investment with big dividends!--NBC

Fred

Is that water hammer further away from the radiator? That is also a sign of water pooling somewhere. It sounds like you took care of one low spot but still have another, probably somewhere along the Main.

Kjmass1

I'll monitor the next couple heating cycles to see if the hammer continues or if it was only for the first cycle.