addding radiation to steam system

ryan_7

I have a customer who's mother had an addition added to her house this summer. She has a two pipe steam system with a mixture of radiators and baseboard. The contractor added baseboard in the addition. The new baseboard will not heat. The other guys won't return and the owner is asking my opinion of what is wrong.
I noticed there is no steam traps on the new baseboard. I see the existing baseboard has hoffman number 8 valves, (I am assuming a steam trap) on the return. But I also see on some of the radiation in the old part, there are dole air vents. I guess I am kind of confused. On a two pipe system do you use steam traps or air vents? Since there is no trap on the new baseboard. Can I add a air vent to make it work?.
One other thing, they piped all the new baseboard with copper. What kind of problem will this be in the future?.
Ryan

Steamhead (in transit)

That sounds like a hybrid system

or one that has been butchered. You need to ascertain what it originally was.

If all the radiation except the new baseboard has traps like those Hoffman #8 units, there should be no air vents at all on the radiation. The air passes thru the traps into the dry (overhead) return and out thru a central air vent in the basement. With Hoffman #8 traps this should be a Hoffman "Controlled heat" Vapor system. If you go into the basement you will probably find a Differential Loop or a Return Trap near the boiler. In this case, add a trap to the end of the baseboard and run the trap discharge into the dry return.

If the original radiators have shutoff valves on the returns as well as the supplies, and air vents, the system was originally two-pipe air-vent. In this case the baseboard with traps was added later. You can either trap the new baseboard as above, or run the baseboard return into a wet return or water seal and put a vent on the baseboard outlet.

ryan

I have been reading Dan's book

Could it be, someone at sometime, added air vents to a couple of the radiators when the traps failed?
Anyway, can I add a trap to the outlet of the baseboard or does it need a drip leg?
And what do you think about the copper piping, does that need to be changed?

Steamhead (in transit)

That's probably what happened

but there was also a two-pipe system that did use vents, which is why I mentioned all that.

If the baseboard goes into a dry return to which other rad traps are connected, the solution is simple- put a trap on the baseboard outlet and let the air and water from the baseboard go into the dry return. The pipe carrying steam to the baseboard should be changed to black steel. The return can be left copper downstream of the trap, since the trap blocks the steam.