Two pipe steam system that looks more like one pipe

Rojojr13

Hi all,

Thanks for this message board. I purchased a home (rental property) that has a two pipe steam system. When I first turned it on for the season there was a tremendous water hammer. The pipes were banging so hard that rust was flying off. I bought Dan's book and read it and fixed the system. I works great now. There were several problems. The pressuretrol was set correctly but was clogged so badly that it was not functioning at all. The pressure in the system would rise and push the condensate up into the return mains and then shut the system off as a result of low water. All of the steam traps were bad and the main vent was not functioning and had be replaced with a vacuum style vent. I added additional venting and replaced the pressuretrol and all steam traps. All is well now. It got me looking at my system in my house. I have had small problems with it since a friend installed. He is a plumber but most likely does not work on steam very often. It also appears to be an oddball system. It is two pipe but has a main vent at the end of the main rather than at the end of the return. It also has vents on every radiator like a one pipe system would have. There are several other issues that I will be correcting. The Hartford loop top leg is too long so there is slight water hammering, especially when the water level in the boiler is on the lower side.

The house was originally provided steam from a neighborhood steam plan. This may be the reason there are vents on the radiators. I am curious if anyone has run into this oddball type of system. Should i remove the radiator vents and install main vents on the dry returns as most two pipe systems use? I would be grateful for any input or suggestions.

KC_Jones

Is it possible you have this? REad that article. The dead giveaway if you have that system is the pipe size which is mentioned in the article. Read the article and post back.
https://heatinghelp.com/systems-help-center/two-pipe-air-vent-steam-heating/

Rojojr13

KC,

Thanks for the reply. I remember reading that article either in the book or on the web. That seems to be exactly what I have. There are no steam traps on my system which I did not mention before.

It seems to me that this system would be less efficient than a traditional two pipe system. Since the steam would be everywhere, it would be hearing the wall cavities on the return side. The system works so I guess that I will not be changing it unless there are good reasons to do so that I did not think of.

Thanks again.