Pushing the limits of radiator tapping size

Patrick_North

<span style="font-size:12pt">Gentlemen,</span>

<span style="font-size:12pt">I've got one-pipe steam. Recently I purchased the Radiator of My Dreams as part of a bathroom renovation. Unfortunately, the radiator seems to have been intended for a two pipe setup, and it's tappings are quite small. Here's the facts:</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">Radiator EDR: Approximately 30</span>

<span style="font-size:12pt">Radiator inlet/outlet tappings: 3/4"</span>

<span style="font-size:12pt">Steam service pipe at this location: 1 1/4"</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">At a minimum, I'm thinking of keeping the valve at 1 1/4" then reducing to 3/4 for the radiator connection (rather than using a 3/4" valve), and using a slow vent. From what I can glean from Dan's books, this is really pushing things and frankly I'm expecting it won't work that well. Did I mention this is the radiator of my dreams? Any thoughts on how well this will work? I'm wondering though... I happen to have a Ridgid 300  in the basement, time, and a penchant for chasing windmills. What do you all think about the possibility of piping this as a two pipe radiator? </span>

<span style="font-size:12pt">I'm open to ideas.</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">Thanks,</span>

<span style="font-size:12pt">Patrick</span>

RDSTEAM

bushings??

does this dream rad have bushings that you can take out and size up??  In the past I have installed cast iron baseboard in place of copper convectors. copper convectors would be 1 1/4" but the cast was 3/4" (this was done because of my boss not my first choice). they didn't really work all that well, more of a hit or miss. besides the fact that these systems had been poorly maintained and running pressures that we're probably more beneficial at a power plant, the vents would typically spit water. not saying you will get this issue, but you may. I'm a little dry in the steam department since i don't get to see it anymore, but my best suggestion would be to give it a shot but keep you boiler pressure extremely low between 8 and 16 ounces and see what happens. make sure your venting is solid!!!! MAINS AND TAKEOFFS

Patrick_North

Nope-

... no bushings. Alas, 3/4" is really it. And yes, yes pressure is nice and low (barely a few ounces) and well vented.

Thanks,

Patrick

Rod

2 Pipe Steam

Hi- If it's reasonably feasible, I'd hook it up as two pipe steam. I did this with an over sized bathroom radiator so I could throttle it a bit as it was turning the bathroom into a sauna..On the other hand it was very nice to be able to have a WARM bathroom by opening up the valve when you came home in the dead of winter.  I still have thoughts about putting a TRV on the intake side but since the throttling seems to work fine that may not come about for a while... if ever.

- Rod

Patrick_North

Cool.

I sure could pipe it as a 2-pipe radiator. What "flavor" of two pipe setup seems most appropriate,given that a) this radiator isn't particularly oversized and won't benefit from throttling back input, and b) being part of an otherwise 1-pipe system?

Thanks,

Patrick 

Rod

One Pipe to Two Pipe Radiator

Probably the easiest is to run a drip line straight to the Wet Return and install a radiator vent on the radiator to allow the air to escape. (TLAOSH - Page 125- diagram left hand column)  You avoid having to use traps this way. If routing to a dry return is a better option, you can use a "loop seal" (TLAOSH - page 88)  with a Vent on the radiator.

Possibly the pros have a better suggestion.

- Rod

Patrick_North

Two-pipe with vents or trap?

Interesting. Is this what you did with your oddball two-pipe rad? I suppose if I'm going to the trouble of adding a drip to the wet return (this rad is on the second floor) then including a trap rather than a vent (while a bit cheaper overall) probably requires negligibly more effort.

Anyone have an opinion on which method would work better, or have other suggestions altogether?

Thanks,

Patrick

Rod

One Pipe to Two Pipe Radiator

I ran my drip into the Wet Return and left the radiator vent in place on the radiator.  I did this for two reasons:  I wanted to be able to throttle down the radiator and it got me past some problems caused by  suspected  “knuckleheading” on the intake pipe buried somewhere in the walls. I would have  ripped out the wall however since the house is old and the walls are wood lath and horse hair plastic, didn’t want to go there.



The two considerations you have to keep in mind are:

1. How does the condensate get back to the boiler?

2. How does the air escape from the radiator?



If you use a trap on the exit pipe, you would still need someway for the air to escape.

You also have the problem of where do you lead the condensate. You can’t just lead it straight to the dry return as there is steam present there (unless there is a trap between the steam main and the dry return)   If you don’t have a tapped hole on the radiator for a radiator vent or are using a radiator trap you can install a vent on the drip line. Since the radiator is on the second floor, you shouldn’t have a problem with the “B” dimension, but keep that in mind if you put a vent on the return line. It would still need to lead to the Wet Return or a Loop Seal.



If it isn't too much trouble, maybe you should just try the 1 1/4 valve to 3/4 pipe used with a very slow vent just to see if that has a chance of working.  I would do it fairly early in your renovating just in case you need to go back and do Plan “B”.

- Rod

Patrick_North

Gotcha-

When you said "throttling" I immediately imagined some sort of inlet valve with an orifice to control input, but I guess the air vent offers similar control. Not sure where one would find such a valve these days, anyway. This sounds like a good plan- pipe it as one pipe, test, and then continue piing in the drip to the wet return if (and probably when) there are problems. Luckily the rad is directly over closet space on the first floor so adding in the drip isn't that disrutive.

Thanks for walking me through this, Rod! I'll post pix when it's done.

Thanks,

Patrick