is this a vent or a air repellent?

rohan_1794 · January 3

20251231_092108.jpg

What is the use case and should this be replaced?

mattmia2 · January 3

it is a very old style of air vent. is this a 2 pipe vapor system?

rohan_1794 · January 3

Yes, this is a two pipe steam system. I also have these types of valves at the return lines. I am wondering if it would be good to replace it with new updated air vents.

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mattmia2 · January 3

what do the radiator valves and and radiator return fittings say? that first device may be an air vent that is designed to hold vacuum. actually they may all be vacuum vents.

Big Ed_4 · January 3

How is the system working ?

rohan_1794 · January 3

This is the system. The radiator valves are a mix of spirax sarco thermodynamic steam trap and old Richardson Heat fittings.

Steamhead · January 3

That's a later version of the Richardson system. You can find it in chapter 15 of @DanHolohan 's book "The Lost Art of Steam Heating".

The fittings at the radiator return connections are water seals with small holes drilled in them to vent air. They're different from those in the book but they work the same way.

The T-shaped vent is original to the system. The other two were added later by drilling and tapping the pipe or fitting. They should all be upgraded.

Where are you located?

mattmia2 · January 3

i was actually thinking that was the air vent for a richardson system but i wasn't 100% sure. the boiler pressure should be kept very low, either by bein matched to the system to a bit undersized or by controlling it with a vaporstat

rohan_1794 · January 3

@Steamhead I'm located in NYC, this system was maintained by my father who has passed away. Some radiators are very hot, some don't even heat up. Thankfully we have heat in the rooms used. When you say they should all be upgraded, can you specify what I would need. I plan to purchase a vaporstat to help since joining this site, I have seen a lot of recommendations to use a vaporstat.

rohan_1794 · January 4

Also taking a look into the t shape vent is see something, not sure if that's how it should be.

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mattmia2 · January 4

i suspect that flap is a vacuum check. i think they call it something else but i think it is essentially a vacuum air vent

Steamhead · January 4

https://forum.heatinghelp.com/discussion/comment/1880713#Comment_1880713

Quite a few good steam guys here:

https://heatinghelp.com/find-a-contractor/state/NY/

mattmia2 · January 4

i bet the radiators that don't heat are on the same return vent although steam in the returns will do it too.

109A_5 · January 4

Are the holes that the air needs to escape from painted closed ?

rohan_1794 · January 4

@109A_5 yes it was, but I cleaned it out and now the vent has holes. I'm sure these can be changed our according to steam heads comments just not sure what type/brand.

Steamhead · January 4

@rohan_1794 , how long is each steam main, and what pipe size?

mattmia2 · January 4

are any of the returns as hot as the mains?

rohan_1794 · January 4

@mattmia2 No none of the returns are hot. Some closet to the boiler are warm.

mattmia2 · January 4

then it is probably the vents or possibly things that used to be below the water line that no longer are or excessive pressure pushing through a water seal

109A_5 · January 4

If you have The Lost Art of Steam Heating Revisited on page 428, 429 there are some examples that look a lot like parts of your system.

HVACNUT · January 4

Might as well repipe the boiler correctly while you're at it. If you're gonna do it, do it.

rohan_1794 · January 4

@HVACNUT what's wrong with the boiler piping?

HVACNUT · January 4

https://forum.heatinghelp.com/discussion/comment/1880795#Comment_1880795

The supply should be after the risers, not between.

mattmia2 · January 4

the riser to the mains should be after the risers from the boiler. the way it is now the risers from the boiler are pushing any water in the header up the riser to the main instead of down to the return through the equalizer. the header may be too small too.

rohan_1794 · January 5

@mattmia2 thanks I will make it a project this summer. I would also need to replace each vent correct? Do you have a recommendation for air vents/brand types?

Steamhead · January 5

@rohan_1794 , that's why I asked how long is each steam main, and what pipe size? This is how we size vents.

rohan_1794 · January 6

@Steamhead I have attached a rough drawing of what my environment looks like. The pipe size is 2.5inch.

DWG 2026-01-05 201212.png

Steamhead · January 6

https://forum.heatinghelp.com/discussion/comment/1881003#Comment_1881003

Put a Gorton #2 at the end of each long main. The short main might not need one- after you install the Gortons, see if the steam reaches the end of the short main about the same time as the longer ones. If it does, you won't need to vent it.

rohan_1794 · January 6

@Steamhead did that drawing make sense? I thought people were gonna yell at me. Anyways so the plan is to replace the old vents seen in these pictures? These are on the two long mains.

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This is found on the short main return

20251231_092108.jpg

Steamhead · January 6

The T-shaped ones are original Richardson vents. The others appear to have been added later, and are definitely too small.

reggi · January 6

How many Air expellers and other vents are on your piping? Could the Hoffmans be original #2's installed to supplement the Air Expeller? On your drawing could you add the vents and location!..

Your system is interesting. . My condolences on your dad..

rohan_1794 · January 6

@reggi there are 4 vents, two air expeller and two hoffmans. The lines at the end shows where the vents are but I can edit the visio for clarity.

is this a vent or a air repellent?

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