Panting Vents

Tom_42

Hi All,

I have a one-pipe steam system and all the vents on the system are panting and hissing, including the main. I just replaced one of the main vents with a Hoffman #75 and there is still panting. Last year I replaced all the radiator vents with varivalve vents. Could there be sludge in all the radiator valves?

Steamhead

Heavy Breathing

can have a number of causes. I don't think it's the vents. Most often the cause is wet steam, which can be caused by dirty boiler water or improper piping.

If the water in the sight glass is clear, don't assume that means the boiler is clean inside.

When cleaning the boiler, also flush out the wet returns. Lots of dirt collects here too.

The steam piping around the boiler must conform to the manufacturer's specs. And if it's copper, it's wrong.

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Mark Hunt

In another post


you mentioned that the asbestos insulation was removed by the previous owner. They could have affected the pitch on the piping.

If there is a sag or belly in the piping it will cause vents to pant. A puddle of water builds up in a low spot and the steam pushes past it into the radiator. The water can be pushed so that it blocks the steam and what steam did get past condenses forming a vacuum. That is when the vents sucks air back in. I call this the "Lamaze" system.

Take a close look at the piping.

Mark H

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Tom_42

Dirty boiler

I just flushed the boiler several times using the back flow and each time the automatic feed refilled the site glass there was definitely some dirt or oil ahead of the water. I think the boiler definitely needs a good cleaning. The question is how to do it?

Dave Merklein

I would also like to know the best way to do a good cleaning of a dirty boiler???????

Steamhead

Oil ahead of the water

means you need to "skim" the boiler. This gets rid of the oil on the water surface. If the boiler is newer, it probably has a skim port- check your instruction manual for proper procedure. If you don't have the manual and the manufacturer is still in business, they would be happy to send or e-mail a copy.

Dan covers cleaning in "The Lost Art of Steam Heating". If you don't have this, order a copy on the Books and More page of this site.

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