Replacing a steam radiator...

beck

Hi everyone,

We have a one pipe steam radiator system in our house. That is, except for one radiator that is located at the back end of the house. Unfortunately, it was cracked and so it had to be removed. It was a mammoth as far as radiators went, it was about 5' long and 25" tall. We are looking to replace this but I'm not sure if I have to replace it with a two pipe or if I can replace it with a one pipe as all of the others in the house are one pipe. If that is the case, what is the best way to go about this?

Tim_Hodgson

It all depends

on the supply pipe size vs. the radiator size. If you stick to the 2 pipe it is probably safer rather than connecting a large 1 pipe radiator to a small supply valve.

Good Luck,

Tim

jv100

maybe 2 smaller radiators?

I think Dan mentions this in one of his books.  I'm brand new to steam, and did a marathon reading of Dan's steam books over the holiday weekend, so I might be mis-remembering the idea, and the issue he was referring to might be completely different from yours.  I'll see if I can find the passage...

jv100

found it.

Chapter 8 (It's All in the Venting!) in The Lost Art of Steam Heat, p. 113, talks about how smaller radiators are easier to vent and don't overheat the room.  However, I don't know how this relates to your supply issue, as the previous poster mentioned. And, as I mentioned, I'm totally new to steam, so please talk to the pros! 

Good luck.

JV

beck

thank you--

Thanks for the replies..

I'm hoping that we will not need to put in the same size radiator as was there before. The room that is being heated is small, about 10' x 17'. It was a later addition to the house and it was not insulated. When we fixed it up, we insulated all the walls and replaced all the windows. The diameter of the supply pipe is an 1 1/2. Does this sound like an adequate size pipe if we were to put in a radiator that measures 48" long by 24" tall?

jv100

wish I could help you with that, Beck...

...but that is beyond my current knowledge.  I would think you would have no trouble going to a smaller radiator (assuming the larger one worked fine on that same supply), but I'm not certain.  I also don't know if you could change to a 1-pipe from a 2-pipe, because with the 1-pipe rad the piping will have to accomodate both the steam and the condensate.  I hope someone else from the Wall can help!

Good luck.

JV

davidsorkin

Two pipe vs. One pipe

Hi Beck,



I am a steam amateur / hobbyist but this is what I think:



If the radiator you're replacing was a two pipe and it did not have any problems then I would leave it that way. With a two pipe radiator you can use the valve to throttle the steam and control the amount of heat it produces. With one pipe your options to control heat output are a lot more limited because the valve must be either fully opened or fully closed. This is because with one pipe the condensate returns through the same valve where the steam enters but with two pipe it goes through its own pipe.



For over-sized one pipe radiators I like to cover them with insulation.



1 1/2" supply pipe will certainly be big enough regardless. If you want to check for sure you need to know the number of BTUs or EDR (Equivalence of Direct Radiation) of the radiator and the steam pressure (should be < 2 lbs) and then refer to a chart.



If you go two pipe and you have a steam trap replace that too. My guess however is that you don't and the return pipe goes directly to a wet return line (water trap).



Just make sure you pitch the pipes and the radiator correctly so the condensate can all drain out; that way you don't get water hammer!



Regards,

David

Rod

Replacing Steam Radiator

Hi- Attached is a chart which will help you figure out the EDR (heat output in square feet) of the old radiator and of the new one you are considering installing so that you can more accurately compare the heat output of the old and new radiators.



Are you sure it is 1 1/2 inch pipe? I ask as this is rather odd size for radiator piping. Measure the circumference of the pipe. 1 1/2 inch pipe will be close to 6 inches (5.969) .

1 1/4 inch pipe will be just under 5 1/4 inches (5.215) circumference.



Did the old radiator have a trap on the outlet pipe?

- Rod