New Steam Radiator for Bedroom

punkzter

My wife and I are looking to install a "new" radiator in a middle bedroom on our second floor. We have a friend who is getting rid of some old steam radiators from their house, so we have the option of getting a free radiator.

The room is 11x8x8. It has one wall exposed. Above is a heated floor, and below is a heated floor. It has one double pane window. I need to measure to get the dimension.

I went to this site: http://usa.hudsonreed.com/btu-calculator

And I calculated that we'd need 800-1,000 BTUs to heat the room.

I haven't looked at the free radiators yet. It's possible that they are all the same size, and then it's not really an issue. But, if they are different sizes, is my next step to get pictures and dimensions of the radiators to see how much heat they produce?

The room used to have a radiator in it. It was taken out before we bought the house. Should I do any other work to see if the boiler can support the new radiator? Anything else I should look into? I've included pictures of the steam pipe that goes up through the room, and the connection that is already there for the new radiator.

Grallert

You may be able to see the dark stain on the floor where the feet of the previous radiator sat. You might get lucky and match those making the connection that much easier.
At the very least you could extrapolate the size and out put, though it it's not likely you'd not the same BTUs as originally installed.

punkzter

Let me ask this, if they have a radiator that can fit in the space, does it necessarily matter if the BTU isn't perfect? I get that the room might not be warm enough, but it's better than nothing.

I keep reading about designing these systems, and I appreciate the effort. But can I harm my current system by putting in the wrong radiator?

JUGHNE

How uncomfortable is the room now?
Do you have another room about this size that has a rad in it?
A main consideration is the number of outside walls and windows.
If you go oversize the room may overheat. That could be controlled by a TRV on the air vent of the rad...not the steam valve on the inlet of the rad.
The old foot print is good advice, however height will make a difference in heat output.

It is doubtful you would exceed the limits of your boiler. Most are over sized already.

punkzter

I'll check out the footprints when I get home. You can't see it in the picture, but the wall that the radiator would site parallel to has a window that is somewhat low. So I'm guessing that our main limitation will be the size of the radiator that can fit in that spot. And they may not have one that will fit.

But I think that this puts me on the right path.

The room gets cold, I never calculated the differential in temperature between it and a heated room in the winter. But it was clear that the steam pipe running up through it was not adequate. But the window is a new(ish) Anderson double pane window, so that helps some.

EBEBRATT-Ed

If the room only really needs 800-1000 btus (that's pretty low, like a closet) then almost any radiator will probably overheat the room.

You can try controlling it with an adjustable air vent (which probably wont work)

A TRV as @JUGHNE mentioned is the answer.

Or skip the steam and put a small pc of electric baseboard in.

WAIT, let me put my hardhat on!!

acwagner

Just curious, what kind of existing radiators do you have in the rest of the house, big freestanding cast iron ones or convector type?

800-1,000 BTUs is a small amount when it comes to old radiators. If they have varying sizes, just grab the smallest. It will almost certainly be much larger than that need if it's a cast iron radiator. For perspective, even the smallest brand new cast iron radiator from Burnham is almost 1,600 BTUs (that's roughly 7" wide, 7" deep, and 19" tall).

You could also look at a comparable room in your house and go for a radiator similar in size to the one in that room.

And, looking at your photo, the connection to the proposed radiator location looks pretty close to the floor. You might have to do some creative pipe work to connect the new radiator to that existing pipe depending on the type and how far off the floor the connection on the new radiator is. Measure off the floor to the center of the connection and take that measurement with you when you go look at the radiator. Free is free, but if pipe fitting isn't your thing you might spend more time/money trying to make this free one work than just passing on it and finding one that will be easier to hook up. Just my two cents as a fellow homeowner.

Fred

Do you see any signs that it may have had a wall mounted radiator there? Do you have any other wall mounted radiators in the house? That might also explain why that nipple is so low to the floor. It may have had a couple 45's and a short nipple with a valve that carried it up to the wall, above the baseboard.
A wall mounted unit like this might work:
Height : 13"
Width: 15 5/8"
Thickness: 2 7/8"
EDR: 5
That would be about 1200 BTU's. It also looks like that riser feeds another radiator on the floor above so you don't want anything that is to big and robs the one above of its steam.

punkzter

All of the radiators in the house a
re the free standing cast iron radiators.

If 800-1,000 BTUs would work for a closet, my calculation must be way off. It's a small room, but I wouldn't call it a closet.

I have seen no signs that the radiator was wall mounted. Based on some marks on the floor, I have to guess that it was there.

The space between the window sill and the pipe is a bit less than 2'.

punkzter

Oh, and that pipe does feed another radiator in the attic. How does that work? I just need to make sure that the one on the 2nd floor (the bedroom) is smaller than the attic radiator?

Fred

Typically a free standing radiator would have set under the window. Do any of the other radiators in your home have an exposed pipe that spans the 2 ft. over to the edge of that window sill, with a valve on the end of it, before connecting to the radiator? I would agree with you, I suspect your calculation on the required BTU's may be off, at least by the standards used when the system was originally installed and before insulation, thermo-pane windows, etc.

punkzter

No, all of the the radiators in the house are in a corner, except for the kitchen. But even that is pretty much directly connected to the pipe.

Fred

If your BTU calculation is anywhere near correct, that steam riser alone should be almost enough to heat that room. Can we see another radiator in the next smallest room in the house?

punkzter

Well, I have no idea if the BTU calculation is correct. The site I used was linked in my original post. But I don't have any way to tell if that is a good site to have used.

I do know that the steam riser was not enough to heat that room last winter, that it was much colder than other rooms on that floor. Though, we had originally thought that it would be adequate. We have a newborn, he's almost 2 months old, and this will ultimately be his room. So it needs to be warm enough for when he makes his way into it.

Anyhow, I've attached pictures of the radiator in the next smallest room. It's also on the second floor. It has 2 exposed walls.

Fred

If that radiator is 26" tall, two column, six sections, that is 16 EDR or 3840 BTU's.
If it is 23" tall, it is 14 EDR or 3360 BTU's. Those are small radiators and I can see that size working in that room.

acwagner

I agree with @Fred that if the free radiators are comparable to that in size you'll be fine. I wouldn't get too hung up on the accuracy of the results of the BTU calculator on that website.

Also, if they still have the valve for the radiator be sure to grab that too. Generally, they are considered a mating pair, so you'll have less chance of a leak if the original valve is used to hook it up to your piping.

Do you plan on hooking the radiator up yourself or hiring someone? I ask because I can see getting that pipe cap off as a challenge. Its so low to the floor and close to the wall, I'm not sure if there's space to use a normal pipe wrench.

punkzter

I have a friend who can help me set this up, and he has some experience working with steam systems. I think that he'll be able to work through this.

We stopped over to look at the radiators tonight, and it looked like we had two options that could work in our space.

This is the first:



This radiator was 18" wide, 30" tall from floor to top, and 4.5" deep.

The second was this one:



This radiator was 35" wide, 20" tall, and 8" deep.

Would you be able to calculate the BTUs of those units from this information? Just a rough calculation...I'm sorry, because I realize I should have gotten the width of each section, and didn't.

EBEBRATT-Ed

use the smaller one

JUGHNE

That would equate to the lighter one wouldn't it?

punkzter

Can you clarify which one is the the smaller one? And why that one?

punkzter

We might not be be able to fit the taller one in the space that we'd like it to go. If we had to go with the wider shorter unit, is our main concern that it could get too hot, and thats it could rob steam from the radiator above it?

acwagner

I believe the first one is around 4300 BTUs and the second is around 7700 BTUs.

punkzter

Ah, wow, so that would be much more that that room needs.

AMservices

Radiators are very flexible with there heating out put.
https://heatinghelp.com/heating-museum/radiator-enclosures/

https://heatinghelp.com/systems-help-center/radiator-colors/

Changing the color, building enclosures, TRV's, slowing the venting.

Whatever rad weights less is the one you want and you can make it work.

acwagner

Maybe. The tall one isn't too much bigger in terms of heat output than the radiators in your other rooms. The short one might be overkill. But, as others have stated, there are ways to deal with an oversized radiator.

How many radiators are connected to that pipe going into the attic? Is that radiator(s) similar in size to other radiators in your house?

punkzter

Only one other radiator is connected to that pipe (the one in the attic). That radiator is 18" wide, 35" tall, and 6.5" deep. It looks like each section is about 2" wide.

As far as the other radiators in the house go, I'd say that most are definitely larger than the small radiator in our back room. We do have one in the bathroom that would be on the smaller side.

The full list is:

Living Room
Kitchen
2nd Story Master Bedroom
2nd Story back bedroom
2nd story bathroom
Attic (finished room)

I've included a picture of the attic radiator below.

acwagner

I think you'll be fine with either radiator. There's a general limit to the amount of steam a pipe can handle, but I don't think you'll be even close to exceeding it with those radiators. You may have to adjust the venting on the attic radiator after you add the new radiator to keep them balanced.

mikeg2015

The issue isn't the output of the radiator. It's the proportional output of the radiator compared to all the others because you have to factor in the boiler duty cycle.

So it's best to look at percentages of capacity and percentages of heat loss of each room. Make sense?

So if the whole house is lets say an EDR of 500. There are 10 rooms and all were the same size, so 50 EDR in each room, if you add a room that's 1/2 the size of the others, you'd want a 25 EDR radiator.

Now it's complicated a little because your robbing steam off an existing riser, so you'll rob some from that other radiator.

that being said, I'd go with the smaller radiator option that's closest proportionally to others in the house based on head loss.

Then just use a TRV. I have one very small bathroom with a small wall radiator, but it's so small (like 4'x5'...maybe) that it still overheats, so I added a TRV. Works great.

Fred

Use the tall one. It is lesser EDR and will be plenty for that room and can be vented down even more, if need be. That shorter one is much larger EDR. The shorter one is maybe three or four EDR larger than what that room originally had if it was like the ones in your picture.

punkzter

The smaller one is the one we are going to go with. The main problem may be the width of it. 18" is going to cut it very close with the window sill. But, I think we'll pick it up and then see if we can install it. The worst case is that we junk it ourselves.

Fred

@punkzter , you can always trade it out for one of the lower ones, in your house, and use the tall one in a room where it fits better.

JUGHNE

It looks like you may have to use 2 45's and a straight full port valve. This lets you extend the run horizontally and maybe even take it past the window if feasible. But all the piping must slope back to the riser.

punkzter

We ended up getting the smaller radiator, thank you all for your help.

So one more question, I'm going to replace the vent, and I wondered if anyone could help with that choice.

All of my first floor radiators have Hoffman No 40 vents.

The second and third floor vents all have No 1 ventrite vents.

The only difference with this particular radiator is that it is the first radiator on the steam riser. So it's the first radiator on a riser that then goes up to the finished attic radiator.

So would a Hoffman No 40 be appropriate? Or should I put a no 1 ventrite on it?

Thanks!

Gsmith

I like the Ventrite No. 1, the adjustment is easy and it can be set to vent real slow.

punkzter

That's what I was thinking

nicholas bonham-carter

That cap looks to be screwed onto the old valve spud, and it should not be used as a nipple for this connection. Follow Jugne’s suggestion of a full port ball valve, or a gate valve with the stem horizontal, a longer nipple will enable you to adjust for any height differences.—NBC

Fred

The Vent-Rite will give you the flexibility to adjust as needed to balance.

punkzter

Re: Nicholas and Jughne

Thanks for those suggestions. I will be sure to show them to my friend when he comes over to help with the install.

brandonf

> @punkzter said:
> Well, I have no idea if the BTU calculation is correct. The site I used was linked in my original post. But I don't have any way to tell if that is a good site to have used.
>
> I do know that the steam riser was not enough to heat that room last winter, that it was much colder than other rooms on that floor. Though, we had originally thought that it would be adequate. We have a newborn, he's almost 2 months old, and this will ultimately be his room. So it needs to be warm enough for when he makes his way into it.
>
> Anyhow, I've attached pictures of the radiator in the next smallest room. It's also on the second floor. It has 2 exposed walls.

Ohh you have the radiator I want. Same as my system. Lol. I can clearly see the four marks on the floor where the old radiator sat btw. There's two dark spots and two light spots.