Radiator on back porch

I have read some of the comments in the section already but I wanted to see if there was some specific differences.
This is our second winter in the house and we are trying to isolate problems. I have an enclosed back porch that has two heat sources. One is an ancient gas furnace that the the kind people from People's Energy just forced me to stop using because it has out of code and potentially dangerous fittings. The other is a 2'tall x 5'long radiator. The radiator is stone cold. It appears to have water in it but it is very cold. I have found the pipes that lead to it and i think I have opened a shut valve but nothing has changed. What is my next step?

this may sound obvious but have you bled it.

Thanks for the reply. I did bleed it and water runs from the valve.