Can I extend a 1.5" pipe to two new radiators?

Marcus Mead_4

I need to extend heat to the back of my house to include two new rooms we finally finished off.



Right now, we’ve got three rooms:



Room 1 (Mud Room):  15’ by 12’  one huge radiator that is hooked up now to the steam line from the boiler about 34’ in length.  It is the only radiator on that steam line, which comes directly off the boiler.  R13 Fiberglass on all walls, 16” of cellulose in the attic.



Room 2 NEW (SunRoom):  Behind room 1 (Mud Room).   15’ by 10’, the sun room, two walls of windows and French doors.  One big radiator that has not been piped in.  Interior walls have R13 fiberglass, all exterior are brand new Peachtree

high efficiency windows.        



Room 3 NEW (Library): Next to room 2 (Sun Room).   10 by 15, one window (it’s new, high efficiency).  One medium radiator that has not been piped in.  R13 fiberglass in all walls.  Cathedral ceiling, with three 2” sheets of fiberglass reinforced foil backed closed cell foam board insulation.  



The pipe that goes to the radiator in Room 1 is a 1.5” ID pipe.  The big question:  <strong>Can this carry enough steam for all three radiators?  Or, will I need to replace it with a 2” pipe?  </strong>The run will be about 40 feet total (it will only need to extend another six or seven feet. Unfortunately, 30’ of it is through the Crawlspace of Death…  I would need to basically tunnel through this one bucketful at a time.  I am

hoping that is not necessary.



I’ll make sure the venting is under control, and the pipe in the Crawlspace of Death has  1” KnaufFiberglass insulation on it.



Oh, and we live in Northern (cold) Michigan.



I’m hoping that I can extend the existing pipe, but better to ask the experts first! 



Many thanks in advance,



Marcus

Jamie Hall

Well, maybe

Can you figure out the EDR total of the three radiators?  Runouts (which is what that really is, although one could think of it as a main -- a distinction without much of a difference) are sized based on EDR and flow direction.  There are books and tables available on this site to help.  Steam is sized on the basis of connected radiation, not heat loss.



Once you have figured the total EDR of the three radiators, then you can take a look at the pipe size.  A 1 1/2" pipe, properly pitched (1/2" per foot) on a one pipe system will handle up to 81 EDR, or about 20,000 BTU/hr.  If your radiators are really huge, this may not be enough -- but "huge" is one of those adjectives and one man's huge may be another's medium!



Now if that proves to be not enough, there are several possibilities.  One is, since you seem to have really worked on the building envelope in that area, to see if you can go with smaller radiators -- that would keep you from having to go through the crawl space.  Another is if you can repitch the runout towards the far end, and take a pipe from there back down to the wet return -- but that assumes that you can get at the far end, that you can repitch the pipe, and that you can get from the far end back to the boiler without major problems!  That would increase the capacity of that pipe to an EDR of 224 which would probably be ample.

Marcus Mead_4

The wet return

Okay, I will look into the EDR, but it sounds like a wet return will give us substantially more heat?



I understand the concept, and I'm sure I can do it, but as you said, that would mean changing the pitch of the pipe, adding a return pipe, and that means a trip into the Crawlspace of Death.



But I want to do this right first time.  And the wet return gives me a lot more heat, even in a 1.5" pipe?

Marcus Mead_4

EDR calcs

I just did a rough EDR calc based on my pics.  I used this site:  http://www.colonialsupply.com/resources/radiator3.htm



Since I couldn't find the info here.  It looked right, anyway...



Huge one in mud room:  15 sections * 2.5 = 38

Big one in Sun Room:  10 Sections *2.5 = 25

Medium one in Library:  8 Sections * 2.5 = 20



So that adds up to 83?  So the pipe can handle it?



But I don't think it holds a pitch quite 1/2 inch per foot...



Thanks so much already for the help!

Jamie Hall

It's worth the try

You are close enough on the EDR that it might well work OK, without more effort -- the ratings are a bit conservative.  I would get as close to the 1/2" pitch as I could, though, without venturing into the crawl space of death, as that will help a lot.  The worst that will happen is that you will get a water hammer in there, and only then will it be time for plan B...

Marcus Mead_4

Go for it!

That's great!  There is no water hammer so far (it's been this way for about six years now), and I should be able to keep the existing pitch (although I will have to reinforce the joists, because I will be cutting into them more than code would allow.)



But I am very hopefully!  Worst case, I'll have to re-do it with a wet return, but I will be able to re-use the 1.5" pipe, so I won't be wasting money extending the existing one.



I really appreciate it!  Thanks for the advice!



Marcus

jpf321

figuring EDR

you said nothing of the rad height in your calcs above .. you need to have factored height as well as #sections... perhaps you did and neglected to make it clear.

Marcus Mead_4

Figuring EDR

I calculated from work, and was guessing that the radiators were 32" high.



They actually measure 38" high now that I am home (from the floor to the top, including the feet.)



That makes a big difference;



15 *3 = 45  +   10*3 =30   +   8*3 = 24  +  99 total, well above the 81 we were shooting for. 



Options include:



-  Break up the huge 15 section radiator, it's much bigger than a 150 sq foot room needs, make it 10.  Then we are back to 84, which would work.



-  Use the radiator huge, knowing it will never get filled up with steam.  Is that a problem?  This would be my first choice since it is easy, if it will work.



-  Go find another smaller radiator....



-  Crawlspace of Death for new pipes.



Anyone have a thought about what would work best?

Marcus Mead_4

Into the darkness...

Okay, just came out of the crawlspace of death.  I did find bones, ironically...



I've decided to burrow my way back to the basement and boiler, so that I can make the one-pipe line a two pipe with a wet return.  Lots of dirt, one bucket at a time, but I only want to do this once, and the two pipe run is my best bet for that.



Just last questions-  What pitch will the main pipe need to be (pitched down this time, not up)? 



And the return pipe- how big a return will a 1.5" supply require, and how much pitch will it need to get the water back to the boiler?



The return pipe, if it needs the same pitch as the main one, may require quite a bit of dirt removal.



Thank you!

Unknown

2 pipe makes sense

Do you have a copy of "The Lost Art of Steam Heating"? If not, I think it would be very beneficial to you  to have one as it has all the figures you need like pitch etc. While we can provide those for you, the "Lost Art..." may give you answers to questions you hadn't thought to ask. http://www.heatinghelp.com/products/Books/5/68/Lost-Art-Of-Steam-Heating

I've attached a EDR chart which might be of help to you as you could compare it with the other one you already have. Ithink you smart thinking about going two pipe as you'll have much more control over the heat in the individual rooms and also won't have to worry about pipe size. The "Lost Art..." covers all the design info necessary to install a 2 pipe system.

- Rod

Marcus Mead_4

I will soon!

You know, after I posted that last message, I realized I just need to order the book!



So it's on the way!  I'm sure I'm not the first person to ask that question, but there are so many thousands of threads, it's really tough to find.



Thanks for the reply, I'll check out that attachment, and read the book as soon as it gets here.

Unknown

"The Lost Art...."

I didn't mean to sound like we were "brushing you off" as we're always happy to answer questions. It's just that "The Lost Art...." has diagrams and all the information on the parameters for different types of steam systems and having that in front of you is a great help as it makes what you are trying to accomplish a lot easier to understand.

- Rod

Marcus Mead_4

Not at all!

I didn't think you were brushing me off! Actually,  teach computer science at our local middle school, and use this site as an example to my students of how you can find answers to questions if you ask nicely!



I need the book, it's overdue!



And I do think I found the answer on Hoffman's site as well, as far as the pitch goes.  Check out the pic, it looks like I can drop an inch over 20 feet, which is very do-able, even in the crawlspace of death.  Oh, and I mis-spoke, it is a DRY return, not wet.



Speaking of, we're now about 20' in, with about 8' to go.  It the ground is real hard to punch through, especially when you are crawling through a newly dug tunnel, and dragging out buckets one at a time, but grandpa always told me, "Do it right the FIRST time."   Right after he told me to do it myself... 

Unknown

System

I 've been looking over your setup and keep thinking about piping the new radiators as at two pipe system.  When you receive "the Lost Art .." you might want to take a look at the 2 pipe system info. A two pipe system has a lot of benefits over the one pipe system. With a  2 pipe radiator you can use the intake valve to throttle down the radiator if you are getting too much heat.  This problem is quite common with sunrooms.

Are you familiar with TRVs? You probably  going to find you will need to use TRVs with a one pipe system. They work pretty well also on a two pipe system though be able to throttle the radiators does the same thing. Either a one pipe or 2 pipe system will work fine. I just wanted to mention it so you can consider all options.

- Rod

Marcus Mead_4

the problem with two pipes...

The only problem with two pipes is that on two of the radiators, there is only one way into them (no threaded port on the other side).  I've never seen a radiator like that before, but that's what I've got to work with. 



On the third one, I once tried to remove the plug in the opposite end, with my humongous pipe wrench (I think it's a 36"), and tore the plug to shreds without moving it.  So I don't think that one is coming out either...



One way in, one way out for all three.  So I'll have to even things out with venting as much as possible.