steam radiator air vent location

David Saxen

I recently purchased a wall mounted steam radiator from "steamradiators.com" for a 1-pipe steam system. The radiator has 1" NPT tappings at each corner of the radiator. For a 1-pipe applications, a plug with a 1/8" vent tapping is used in one of the corners. I have been told by the installer that the air vent will not work properly if it is at the top of the radiator, as the steam will rise to the top and close it before all of the air can escape. The vent apparently needs to be +/- half way down the side of the radiator (as it is on my older free-standing radiators) to function properly. Steamradiators.com says that the vent will work fine in any of the NPT tappings.

Any input on this debate would be greatly appreciated.

Thank you.

Daniel_3

From experience it has to be down at the bottom as is tapped for an A@R co peerless wall rad. If not it will snap before the air escapes. The only cast iron radiator that will work (and this is the only way) is a cast iron baseboard where the tapping is the high point. If it's a block type rad like I assume it is then there should be a boss to tap into down low (maybe it already has a slotted plug in there).

David Efflandt_2

Their docs do not address that

Their photos show steam vents at the top, but at least one of those is a vertical vent mounted horizontally (not sure if the other is a TRV). But their instructions for 1-pipe do not mention where the vent should go (just that one plug has 1/8" tap). There does not appear to be an optimum place to put a vent. Top would tend to close too soon (steam is lighter than air) and bottom might tend to collect condensate.

Daniel_3

One of those last pictures shows a Hoffman 40, a super slow vent in comparison to other common adjustables and the gorton line. Because of the slower venting rate it could be a non-issue since the air would be slow to escape leaving a more evenly charged rad. I would just drill and tap into the bottom third of the last column and tap. Although unless you have a steady hand it may not be a good idea.

Brad White_185

You make a good point

about those from SteamRadiators.com. While they are nice looking, the vent locations in either spot are not ideal.

If I had to do it the traditional way (about 1/3 the way up from the bottom and opposite the inlet side) and could not make a new vent tap, this is what I would do:

Pipe a "U" or "D" loop consisting of a very short brass nipple in a bushing off each far-end tapping. Connect these together vertically with elbows, nipples and a union to form the aforementioned "D" loop. In this loop I would place a tee 1/3 the way from the bottom. This would allow the radiator to properly fill with steam before shutting the vent. But it might look stupid! Oh well, better that than not making use of all of your EDR...

My $0.02

David Saxen

Thanks everyone for your thoughts. I will forward this thread to the manufacturer. It certainly seems like a false claim to say that these radiators can be used in a one pipe steam application.