How To Add Radiator to Current Hot Water System

netguy7

Hi.  We have a hot water heating system in our house.  I am attempting to

install an old cast iron radiator into the bathroom.  There used to be a large

one in the room but the previous owner removed and replaced it with a small

baseboard type that does not provide nearly enough heat for the size of the

room.  So I have two pipes coming up through the floor that I plan to tap into

using the vent caps to access them as I plan to leave the existing baseboard

heater in place.  The fittings I plan to access are pointing straight up  (the

baseboard is connected from the side of each of the cone type fittings on the

top of each pipe).



One of the vent fittings appears to be 3/4" and the

other 1/2".  Would it be reasonable to assume that the 3/4 fitting is the supply

line or ?  Short of waiting till the system cools and then starting it again and

placing my hands on each pipe to see which one warms first, how can I determine

which side is the supply side?  Does it even matter?



The radiator is 32"

tall - 8 ribs long and 6 ribs wide.  The fittings on the bottom of each narrow

side of the radiator had been used previously in its original application.  The

vent is on the top of one side.  Should I place the supply line into the side

with the vent above and use the shutoff valve on this side too or ?



I

plan to use 3/4" copper pipe and fittings even though the radiators original

fittings are 1/2" on the outgoing side of the fitting (3/4 on the ingoing

side).  Should I connect to the original galvanized steel female fittings from

the radiator with copper male fittings or use something else to connect the

copper pipes?  Should I just use plumbers tape or something else on the

threads?  Any other tips or concerns about this?



Finally, I plan to

install shutoff valves on each line that have a bleeder and that seal with

compression fittings (that screw on and off) so that I can easily remove the

radiator in the summer months and easily reinstall it again before winter if I

want to.  Any concerns about this?



Thanks Much!