Can I DIY this radiator downsizing?

lateralex

Hi. I have a rather large steam rad by our front door that we have turned off completely the last few years. With a new baby on the way, I'd like to downsize the radiator to get a a tiny bit of heat - but reclaim the space back that this radiator is occupying (and this new smaller rad one would let us built a bench over it for putting shoes on for instance).

I have the new cast iron radiator, and the right bushings for 3 of its' sides. The connection to the existing valve is where I'm unsure if I can get the part needed. The new smaller radiator has ID 3/4" threads, and the existing radiator valve is ID 1 1/2". Is it possible to reduce the 1 1/2" to 3/4" without replacing the entire valve? If so, can someone point me to the right part. If that is viable I would then pickup a spund tool to reclaim the union from the old radiator - but if this is impossible, no point going through those steps if I will need to get my plumber to install a new valve altogether. Here are a few pics in case it is helpful. Thank you.

Sailah

A new radiator valve is pretty cheap and they would come with a new union nut and tailpiece which is what is attached to the larger radiator.

I have tailpieces but it would be a guessing game to see what fit. A tailpiece often has a matching flare to mate with the valve and they are all a little different. Based on the size of the valve that looks like a big union nut and that is harder to find. Most of mine for radiator traps are considerably smaller. If you can get me a measurement of the ID of the valve and the OD of the tailpiece I'll see what I can find Monday

I would just replace the valve assuming you can get a wrench on the pipe. What's the pipe size?

Danny Scully

Cast iron baseboard is not designed for use in a 1-pipe steam system, or is this 2-pipe? This isn't to say it isn't commonly used in 1-pipe steam systems, however, it's not ideal. This is due to its 3/4" tappings. Minimum tapping size should be 1". If cast iron baseboard is the only option, I suggested installing a Vaporstat to lower your pressure in the ounces range and using a radiator elbow, not a hand valve. This will maximize the ability of the condensate to exit the radiator. As I write this, I guess the quicker answer would be no, this is not a diy project. Where are you located?

lateralex

A few answers - here is the view of the current valve. It looks like 1 1/4" steam pipe below it based on the marking and I do think I could easily wrench it off. If I wanted a not-so-elegant solution, could I remove the current valve, attach a reducer (like the one in the screenshot below), and then buy a new 3/4" valve to attach to that? I think the trade-off is the new radiator would now be a few inches higher and need some built up wooden platform - which we could probably live with.

Danny to your question I'm in the Boston area. I have a text out to my general plumber but not sure if steam heat is his bally-wick.

Danny Scully

You'd have to put that reduced on the vertical, so you'd be even higher at that point. You might want to reverse your idea though. Leave the 1-1/4 valve and put the reduced on the 1-1/4 radiator spud and pipe back to the radiator.

lateralex

I follow you, good idea. So go something like:
New rad > 3/4" nipple > 3/4" to 1 1/4 bushing > 1/14 spud.

Danny Scully

Yes, a coupling though, not a bushing,

lateralex

And... it's done. We have heat. The little sucker puts out more than we would probably need. Appreciate the help!

Danny Scully

The vent should be on the upper tapping, or even branched off the center of a connection between both tappings. It's likely to spit water were it's currently located. You made quick work of things though! Nice.