Steam riser with no air vent or radiators?

bipbap

We have a steam riser that used to serve bathrooms with radiators.
The radiators were disconnected long ago leaving just the riser with a air vent at top.

Just curious, what would happen if there was no air vent on a 3-story steam riser with no radiators attached either? Would it not get hot at all?

ethicalpaul

With no air vent it won't get hot. At the very bottom near the main it might get warm (depends how near and how long the boiler is running).

bipbap

Ok I see.
wnat size vent should be at the top of a riser like that? It goes from basement to the 2nd floor and the riser dead ends in the ceiling with a cap and has no radiators attached.

ethicalpaul

I'm a little confused by your question. What is your goal?

If your goal is to have a hot pipe, you could put a Maid O' Mist #1 or Gorton #1 on top of it.

dopey27177

Bot the Maid o Mist and Gorton 1 are fine. The riser gives off about 1/2 EDR per linear foot, just enough to take out some chil.

Jake

bipbap

Sorry my goal is to keep that pipe hot to serve as heat for the two bathrooms it runs up through.

ethicalpaul

Ahh OK the pipe will be hot in that case. Whether it will heat the bathrooms depends on other variables. Good luck!

https://www.supplyhouse.com/Jacobus-Maid-O-Mist-J1-1-3-4-x-1-2-Main-Vent-Valve-3563000-p

bipbap

Before that riser was vented with just a standard vent like the size you see on the side of a radiator, not one of the larger vertical mounted ones.
would one of those be ok?

ethicalpaul

Yes it would be fine. It might be slower to let the pipe fill with steam is the only difference, but if your steam is on all season that won't matter.

If you get a Maid O' Mist radiator vent like below, you can unscrew and remove the orifice piece from the top and it will be roughly the same venting rate as a #1.

https://www.supplyhouse.com/Jacobus-Maid-O-Mist-J4-4-1-8-Angle-Air-Valve-3564000-p