One Pipe vs. Two?

SteamCoffee

In my readings about Steam, I keep seeing the comment that the 2 Pipe Steam systems were obsolete, the latest from a 1935 textbook. The issue is never address why that is. Is it efficiency or economics? Is there something about a gravity 2 pipe that makes it less efficient? Can anyone elaborate why a 2 pipe would be labeled as such? or was it just the cost of the installation alone? Thanks!

Steamhead

They're talking about

the 2-pipe air-vent system. This had a supply and return connecting to each radiator thru a hand valve, and an air vent of the same type used on one-pipe radiators. In this system, the return connections handled water only, not air.



Later 2-pipe systems use traps, water seals etc. so that the return connection could also handle the venting of air from the radiators. This does away with vents at each radiator. The air is vented at a central point in the basement.

SteamCoffee

Your right! ..I looked again,

Now that makes sense! Now that distinction made, is there any significant efficiency difference with a One Pipe vs. a Two pipe system? What advantages would the labor and materials required, of a two pipe system, bring over a One pipe system? Is piping condensate separately save BTU's? Lots to learn, but trying ! Thanks!

gerry gill

The two pipe

syatem (2 pipe air vent) could be throttled at the inlet valve and the piping would be smaller in diameter.

SteamCoffee

So, is two-pipe

more efficient at getting the BTU's to the radiators? You would think that the counterflow of the one-pipe may cost you some heat? Does the condensate dampen the steam, say early in the heating cycle? Thanks for the input!

SteamCoffee

If you throttle 2 pipe,

what is better, traps or vents?? Or would an orifice at the outlet of the radiator work better? Would the 2 pipe vent be better than more commonly found 2 pipers? 2 pipe gets kudo's for a better, more evenly heated radiator. SLOWLY learning!

jumper

depends

Generally we only examine systems when there's a problem. I suspect that there's two pipe systems from before steam traps that still satisfy their buildings. Especially ones that have original heating demands to preserve character. Regarding SteamCoffee's question about efficiency the answers is that efficiency and economy depend on multiple factors. For example how much fuel do you have to save to pay for changing trap cartridges every ten years ?

gerry gill

Better?

no, i wouldn't think so as the noisy hissing, sputtering air vent is still upstairs instead of in the basement where the two pipe vapor put it.