I had my steam boiler replaced (same size and make). I have a 10 foot long base board heater that is connected to the steam system that now leaks hot water at the vent valve. I replaced it and it still leaks. Should the valve not leak water?
The connection is close to the boiler on the pipe that connects the steam outlet manifold back down to the condensate return. It is above the main condensate return from the house.

 

The steam vent should never leak water. I would think the boiler is surging. Watch the water level in the gage glass on the side of the boiler when it is making steam. Is the water level bouncing more than 1/2" or dropping down near the bottom of the glass. If so the water is going into the system as water and steam instead of just as steam.

 

Although they do make basboard for steam they seldom run trouble free. By the time you get the proper pitch to return the condensate you wouldn't want to look at it. They do recommend puting in a return line back into the main to get rid of the condensate problem. Your boiler does not have to be surging to have baseboard problems. They do not react the same as radiators when it comes to steam.

 

If the baseboard does not exceed 10 ft and you supply one side and return the other you should not have a problem. With that said I see plenty of one pipe CI baseboard that works fine providing there is no surging and the venting is not too fast. Many times the baseboard is blamed for problems when it is a vent venting too fast which means more condensate and the real problem is an undersized or non-operating main line vent. The baseboard may work fine with the old boiler but the new boiler makes steam so much faster the problems arise. The problem existed but was not a problem until the new boiler went in.

 

Or a NON-EXISTENT one too!

Willy, if you want, take some pictures of the system and we'll take a look and see if all looks OK... free account / Image hosting, free photo sharing & video sharing at Photobucket / upload there / post a link here.

 

I have surging. That should be fixed when the steam header piping is corrected by the contractor. 2 risers are between the 2 feeds from the boiler with the equalizer off the end of the header. (I now know a classic mistake.) Funny thing, the old boiler was piped that way with no problem.