aside from any pressure/ safty concerns
The steam coil is most likely has a trap on the condensate side, you should leave the trap and connect the steam supply to the trap. Sound like you should be able to just cap both lines, right? well unless you take a good look at the system there is a chance that the capped supply might begin to accumulate condensate with no where to go. so unless you really know it won't Connect the dots/ pipes
I think you can guess why I know this is possible
You have got to learn from other people's mistakes! Because God knows you don't live long enough to make them all yourself !!!!!!!!