\"pedal valves\" for steam radiator???

Steamhead

but the system is "two-pipe, air-vent". This was the precursor to the Vapor systems we all love. It provided separate return lines for the condensate so the steam pipes were less likely to bang.

The return shutoff is needed to keep steam from finding its way thru the return to the air vent on the shut-off radiator.

You vent the steam mains on this system the same as on a one-pipe system. Do not, however, install vents on the return lines as you would in a Vapor system. The returns in this system only handle condensate, not air.

How about a picture?

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Jim Hynes

pedal valves

I ran across a steam system, which had "pedal Valves" ( that is the actual name brand ) on both ends of the radiator. They are dated @ 1896, with the rads @ 1874. My problem is Ive never seen any of these before....If they act as regular valves, then why need two of them? Is there a steam trap built in? And lastly why do the rads have air vents on a two pipe system???

ed wallace

pedal valves

hi jim was wondering when you would post the wetheads here will know

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Jim Hynes

pedal valves

I'm sorry i dont get it...Isnt the supply for a two pipe supposed to be at the top of the radiator? Secondly are you saying that one of those vales should be closed? If its a true two pipe wont you need both open and why vent a two pipe system. Does these also pre date steam traps? what prevents steam from going in the return?

Ill try to get pics next time I'm there..maybe next week..I have to replace the main vent.

thanx for the input

Jim Hynes

Steamhead

Two-pipe, air-vent

If you want the radiator to heat, both valves should be open. But if you want to shut it off, close both valves. Otherwise steam may enter the rad from the wrong direction.

This type of system evolved from the one-pipe system. It provides a separate path for condensate to return but the air is vented in the same way as on one-pipe. It wasn't until Vapor came out that radiators didn't need air vents.

If each radiator return is piped down into a wet return, steam cannot enter the return. But if several rad returns are connected together above the waterline, steam can enter the return and get into another rad via the return. Keeping the pressure low minimizes the chance of this.

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[Deleted User]

the only system like that

that ive run across here, has the outlets dropping into a wet return, each one individually.