cast iron radiators

JIMBO_2

I am replacing several radiators in a hot water system. But I have several petty questions.

1) The small air vent used to bleed the radiator. Does it really matter if it is atop the supply side or the return side?

2) Is it to my advantage to pipe the supply at the bottom, in on the bottom and out on the other end of the bottom? Or is it better to pipe the supply inat the bottom and the return out the opposite side from the top? Or am I wasting time asking the question?

3) What's the best way to paint cast iron radiator? I've been told that the old silver or gold spray paint is no longer the way to go. I presume, since they seem to rust if it's too humid, that I need to prime them with an oil base primer and then prehaps the color of the room. Yes?

I know it's petty . . . but I'm just trying to get it right, the first time. Thanks

Mike T., Swampeast MO

1) Location of vent doesn't matter as long as it's at the top.

2) You can pretty much use whichever tappings are most convenient on standing iron. Bottom-bottom is probably most common. Supply on top and return on bottom (with valve on supply) is likely the most convenient for operation. Avoid making both connections on the same side unless the rad is only a VERY few sections or you can find or make special fittings to extend one on the inside to the far end. While it's conventional to install a hand valve on the supply side, it's not a necessity. TRVs are directional and must be properly oriented--most always? always? on the supply if you're using an angle valve.

3) Whatever you do to paint, DON'T paint bare iron with latex paint! It will rust through very rapidly. If the current coating is in VERY good shape you can use latex to change the color. Metallic paints do reduce radiation a bit--silver (it's actually aluminum) is the worst in this regard. Special high-temp paints are really overkill. As with ANY paint job, the key is proper preparation!

JIMBO_2

Thanks, Mike, Very helpful. I appreciate it.

netguy7

Radiator Install

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!

Paul48

netguy7

You need to start your own thread, so it recieves the proper attention.