Main steam vent

dc07736

Hi,

I am working on a steam system 100 years old in Kingston NY.
1 pipe system
20 cast iron radiators- present boiler is Burnham natural gas.
Was once coal, then oil now natural gas.
Am presently installing a used Burnham steam boiler 140,000 BTU

No sign of main steam vent, do I need a large vent like this?
Any pipe I cut seams clean, do I need to flush the system?
The valves on the radiators seem to work, is it worth upgrading?

Thank You -Dennis Connors

JohnNY

Find a plugged/capped tee, cut in a tee, or drill and tap to add a proper main vent somewhere about 12" back from the ends of the horizontal steam mains. No 1-pipe system has ever suffered from being vented properly. Air vents get the steam out of the boiler and into the heat emitters. That makes for efficient operation. Always.

BobC

The steam pipes don't need any flushing BUT any returns that have water in them need to be flushed or replaced. Carefully inspect any returns that have water sitting in them because they are rusting from the inside out.

Bob

dc07736

Bob,
Thanks for info,
Burners were completely clogged.
Cleaned the burners, removed jets, they looked clean so we reinstalled.
Original design had no main steam vent,
do you advise one.

Thanks
Dennis Connors
Kingston ny

BobC

Is this two pipe steam? Any signs of it being and old style vapor system? Some of those vented into the chimney. Take a look around and post pictures of anything that looks odd.

Bob

Jamie Hall

If this really is one pipe steam -- double check that! -- then you do indeed need main vent(s) at the end of any steam mains, more or less as @JohnNY suggested.

However, if it is two pipe steam or particularly a vapour system (a variety of two pipe steam) then you may not need main vents on the steam mains -- or you may. Go to the ends of the steam mains and check to see if there are crossover traps to the dry returns. If there are, and they are working, you do not really even want vents there. However, what you do want is main vents where the dry return(s) end and turn down to become wet. You want those whether there are crossover traps or not.

On the valves -- probably no point in messing with them.

New England SteamWorks

The only purpose vents would serve on the mains is to quickly chase the air out so the steam can get to the radiators as quickly as possible. The quicker the steam gets to the radiators the quicker the rooms warm. The quicker the rooms warm the quicker the thermostat is satisfied. The quicker the thermostat is satisfied the shorter the boiler cycle. The shorter the boiler cycle the smaller the fuel bill.

Other than that...

Yes. You need them. Big ones. Call @JohnNY. Maybe he'd like a weekend Upstate. Watch the leaves turn...

gerry gill

I like that description RI

dc07736

System is 1 pipe
20 cast iron radiators
All steam vents are missing from radiators -probably taken for junk value.
Have to buy new ones
Should I use adjustable or plain vents o the radiators?
DC - Kingston NY

BobC

If your starting from scratch, guessing what size vents to use on which radiator can get pricey. Adjustable vents let you experiment, DO NOT BUY the Durst brand at Home Depot - they don't adjust anything.

That leaves you to choose between Hoffman 1A's that can be tricky to adjust and a bit pricey or Maid O Mist 5L's which is a kit with one air vent and 5 different size screw on orifices.

https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias=aps&field-keywords=hoffman+1a

https://www.amazon.com/OMIST-0220-5L-Angle-Steam-Valve/dp/B003DV3AGE/ref=sr_1_2?ie=UTF8&qid=1476618544&sr=8-2&keywords=maid+o+mist+5l

Bob

Pumpguy

Tunstall also offers adjustable radiator vents. PM me for details.

Steamhead

20 radiators and only140,000 BTUH? Sure that's enough?

PMJ

The thing about vents is that while they let air out quickly they also let it back in - quickly. The original system didn't let any air back in when it was heating because the fire never went out. This breathing in and out every cycle is an unfortunate consequence of the on/off fire control. Two pipe systems are easy to control not letting the air back in and will run much more quietly and efficiently that way - I have done it for years now.

On the first cycle air does not have to be vented out quickly because you can't heat the pipes up that quickly - there is plenty of time on that cycle with a small vent. After that most of you need fast venting, but only to get the air back out that you let back in. Seems (is) quite a waste of effort.

Someone needs to figure out something for you one pipers. You are buying a vent for every rad anyway. There must be way. Air is the enemy. Need to keep it out.

SWEI

Would Hoffman #3's work?

dennis53

Very good luck with Swan Vent-Rite #1. Tool free adjustment, scale tracks well, wide range, tough to plug.