steam vs hot water heat


  #1  
Old 09-22-02, 09:29 AM
lavelljs
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steam vs hot water heat

We own a large Victorian house, 5500 sq ft, 3 floors, full basement. Thirty years ago the previous owner removed the hot water cast iron radiators and installed hot water baseboard, which does not heat the house well at all. I contacted several HVAC companies and received quotes to fix/replace the current system as high as $25K. So I am on my own. Over the past 2 years I have installed 2 cast iron radiators replacing the baseboards and intend to eventually replace all of it. I have acquired a collection of 10 hot water radiators of various shapes and sizes. I found a web page that gave me the BTU rating for the "skinny tube" style. Where can I find the BTU's for the "fat tube" and other styles of radiators?
The county courthouse was remodeled this summer, and I purchased all of the steam radiators, over 50. In my ignorance I thought I could use them for hot water but they are strictly steam, as the top of the sections are not connected. I read on your page about converting from steam to water and back. The article mentioned return lines for the steam and condensate. The system in the courthouse had no returns. One big pipe was connected to a large vaccum controlled valve that was connected to the bottom of the radiator. Half way up the opposite end section was a small conical valve with numbers on it. Since there is no return how did this system work? Since I have so many steam radiators, shoud I convert my system to steam? What about steam just on the first floor? Can I use the existing 3/4" pipe, a mix of iron and copper, or will I have to replumb with the 2" iron pipe? Does a steam system heat better than hot water? Is a steam system more efficient than hot water, meaning there would be an eventual return on investment? Thanks for your assistance.
John Lavell
 
  #2  
Old 09-22-02, 02:59 PM
rclhvac
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Try asking this over at
http://forums.invision.net/index.cfm?CFApp=2
They can probably help you more than this forum

Good luck
 
  #3  
Old 09-22-02, 03:59 PM
bigjohn
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Try www.heatinghelp.com They're the steam and hot water experts. At the website you'll find several inexpensive books for sale on steam and hot water systems. There's also an FAQ section that's very helpful.
 
  #4  
Old 09-23-02, 10:32 PM
R
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The cast iron radiators you got from the county courthouse can either be fitted for steam 1-pipe, 2-pipe or hot water. You just have to change the fittings. The conical valve you are referring to is an air vent valve only found on steam 1-pipe systems. To convert the radiator to hot water you have to remove this valve and plug it. You can buy these plugs at any hardware store and they just screw in. Suggest you use teflon tape on the threads. Don't put your air bleeder valve there. You want to get the bleeder valve as high as possible on the side of the radiator. You'll see on both sides of the radiators a place to install these bleeders valves, but you have to look closely. You only have to do one and you choose which side you want the bleeder valve to be. You will need a drill and a tap set. The tap is used to thread the hole you drill to accept the bleeder valve. At the bottom side of the radiator that does not have a pipe connection, you are going to see a plug that is larger than the plug you used for the vent valve. Unscrew that plug and install a nipple. Depending on what you are going to use to connect the radiator determines the nipple. If it is black pipe, then it has to be a union. If it is going to be copper tubing, then a nipple that is threaded on both ends, one side screws into the radiator and the other gets a copper transition fitting screwed on. The problem with sweating copper pipes to radiators is, if you ever have to remove or move the radiator, you have to cut the copper pipe. I prefer unions for that reason.

As far as converting steam to hot water and back. With an original steam system you can, but if the system was originally hot water, you cannot. Steam pipe distribution systems are deliberately pitched to allow condensate to drip back to the boiler. Hot water systems, even gravity hot water systems are not deliberately pitched in the same manner a steam system are. As far as which is better, they are both equal. The sites mentioned in earlier posts are good sites and I strongly suggest that visit them, ask questions and even get one of their books. There is a lot more to this system than I can put on this forum. Pay strict attention to distribution, it is going to play a major factor on how well your home heats.
 
  #5  
Old 09-24-02, 10:42 AM
TheZman
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Resercon,

One thing I would add (that I learned the hard way) about installing new piping in a hot water heating system, is hot plumbing installation rules differ from cold plumbing installation rules.

After I added several radiators in my house everything seemed fine (no leaks) until I sparked the furnace and passed hot water through the new plumbing. All the nipples were leaking on the threaded ends, even though I had plenty of teflon tape wrapped around the threads and the nipples were screwed on fairly tight.

I removed all the pipes on the sweated ends. When I heated the nipples with a propane torch, I noticed I was able to tighten the nipples another 360 degrees. This is because the threaded ends are not cylindrically shaped but rather conically shaped. This solved my problem completely.

Moral of the story: Threaded fixtures on a hot water system need to be tightened when hot.

Regards TheZman
 

Last edited by TheZman; 09-24-02 at 12:23 PM.
  #6  
Old 09-24-02, 11:16 AM
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Originally posted by TheZman
Resercon,

One thing I would add (that I learned the had way) about installing new piping in a hot water heating system, is hot plumbing installation rules differ than cold plumbing installation rules.

After I added several radiators in my house everything seemed fine (no leaks) until I sparked the furnace and passed hot water through the new plumbing. All the nipples were leaking on the threaded ends, even though I had plenty of teflon tape wrapped around the threads and the nipples were screwed on fairly tight.

I removed all the pipes on the sweated ends. When I heated the nipples with a propane torch, I noticed I was able to tighten the nipples another 360 degrees. This is because the threaded ends are not cylindrically shaped but rather conically shaped. This solved my problem completely.

Moral of the story: Threaded fixtures on a hot water system needs to be tightened when hot.

Regards TheZman
When I first started with boilers I was told to make the pipe tight as i could and then get another 1/2 turn on it. Also in all of the boilers we did there always went in a quart of boiler leak compond just for luck and no call back ED
 
 

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