steam radiator too hot water conversion

greg shiflett

i,m going too covert an old two pipe steam system into a hot-water system and would like some advise. first question is is there a good way too remove old steam valves and traps from old radiators without ruining threads. also i will need to remove the 1/8 inch plugs from the tops of old radiators[ any tips]. also does the top location of the existing steam valves work with the bottom returns that will be on the other side of radiator. any other tips will help. thanks in advance.

Steamhead

Greg, before you even pick up a wrench

read the following article which will tell you some of the major pitfalls you can encounter when doing this.......

http://www.heatinghelp.com/newsletter.cfm?Id=22

If this system is residential, it's probably Vapor. Vapor was the Cadillac of heating in its day and, when properly maintained, is still one of the best systems out there. Typically these systems run on 8 ounces of pressure or so. Trying to carry 12 pounds or more of water can cause major leaks in the old pipes and radiators.

Changing those old valves and traps can also be a challenge. They sometimes break off inside the radiator, then you have to get the remains out without messing up the threads. This takes a lot more time and effort than you planned on. And you'll probably have to drill and re-tap the 1/8" plug openings.

You may also have to re-pipe all the return lines. Most of these were never sized large enough to handle water- just air and a bit of condensate.

I find it's much easier and less expensive to fix steam systems rather than to convert them. You can get replacement trap innards from Tunstall or Barnes & Jones, and Tunstall can also rebuild the radiator shutoffs (and change them to TRVs too if you wish) and even the return trap at the boiler if needed. Gorton makes high-quality main air vents which work very well on Vapor. And most boiler manufacturers offer efficient replacement boilers for steam and Vapor systems.

If you're not that experienced with steam or Vapor, you've come to the right place for help.


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Big Ed

Conversion

First off make sure you can use the job's steam radiators for hot water. Some of the old steam radiators sections where not push-nippled across the top & bottom ,only screwed in ,using counter threaded nipples along the bottom sections.

To remove old bushings and plugs you can cut from the center to the threads .Then chisel in the pie sections. You may have to invest into a tap for cleaning the threads afterwards . If you can't remove the small 1/8" plug you can just drill and tap a new hole...

Now what do you mean can you use the top steam valve location and the lower return ? Does the old steam system taps the supply in from the top of the rad?

greg shiflett

thanks for the help yes the steam pipes enter from the top of the radiator and condensate leaves from the bottom of the other side i have done the calulations and found the steam radiators have suffient capacity to heat with hot water the reason for conversion is to gain head room in the basement thanks for any help

Tom_10

also

even if you were to pull off the rad. conversion, remember all the rust and scale inside of them from over the years. I'm guessing that could be trouble at some point