Riser venting question

Schvenzlerman

My home has a 2-pipe steam system with mostly convector rads. I want to install vents at the top of my home's five steam risers, the purpose being faster air venting. For logistical reasons on a few risers, I'm not going to be able to install at the very top. But I could install vents a couple of feet below those riser tops. This is effectively lthe same thinig, isn't it?

nicholas bonham-carter

Faster venting

I would investigate the lack of venting first before putting in extra bandaid vents.

This system probably had enough venting when it was first installed, so the job is to find what has changed (bad traps, saggy pipe), which is now preventing the air from escaping as the steam rises.--NBC

MDNLansing

Rad Plugs

Do you're radiators have 1/8" plugs or tappings in them half way up? A lot of radiators have vent holes that just need to be drilled and tapped. Venting the supply side of the radiator might have the same effect if you must do it. I think I agree with NBC though. If the system isn't venting properly as it is now, somethings changed. Those old dead guys didn't often walk away from systems that didn't work well. They were masters of physics and always made sure their designs were working properly.

Schvenzlerman

Let me clarify

It's a 2-pipe system with venting performed by convector rad steam traps and a boiler feeder air pipe. I want to vent the risers for the same reason that my mains are vented; removing air as quickly as possible will speed steam to the rads. So my question remains: is there any material difference between placing a vent at the top of a riser versus placing one say three feet below the riser?

nicholas bonham-carter

Difference in riser vent placement

No difference as steam moves quickly once the air is out of the way. Surely, the original installer had made sure the air was able to escape from the system quickly, so why isn't it doing so now? Is your pressure too high?--NBC

Schvenzlerman

Our operating pressure

We have very large mains and risers and operate at 4 oz. pressure. The reason why I have interest in installing vents at the top of our risers is because this was recommended in Dan Hollohan's book, The Lost Art of Steam Heating.