1 cold radiator

RMA

I just installed a replacement gas fired steam boiler, all vents replaced, and radiator valves are fully opened. there is one rad that stays cold. The home oner said it was a problem before. ther is a 2" main that that wraps the basement this room is over the garage (un heated) with a 2 x 1 tee and about 12 feet of run to the radiator above. this line is insulated. All is well except this room. do you think it is a broken radiator valve or maybe a blocked 1" line feeding it?
I don't like replacing parts as a proccess of elination.

thfurnitureguy_4

test the rad.

Remove the vent and see if the rad will blow air, and heat up. If it will the problem is likely in the venting. If not I'd look at the supply valve. Are there vents on the main after the cold radiator? are they working fast? You may want to do a calculation for the size and number of main vents needed. Is the water line at the same height as the old boiler (are all the wet returns still wet?) best of luck.

Guy_6

Rough test

You might also try shutting down the vents to some of the other radiators and "force" the steam (or try to) up to that radiator. If it heats up at that point, you know that the line and vent are clear, and the problem lies in the system itself. You may find the answer in playing with the vents.