Steam radiator to Hot water

pipe4zen

Looking at a job, historic building with a one pipe steam system that is undergoing interior renovations. One contractor had quoted converting to hot water , saving radiators and 5 year old Peerless steam boiler.

I suggest steam stays, but now they want to go with hot water and save head room by getting rid of steam pipe, and they want me to give a quote on this. I told them they have steam only radiators and they would not work with water, but other guy says they are convertable. I looked again and maybe two are tube radiators, but others are not. Am I wrong ? I may have to walk away from this one . Take a look at these pics, HB Smith Radiators circa 1922

Jamie Hall

In principle...

they should be convertible.



However.



There is no way -- absolutely no way -- that I would ever recommend trying to convert one pipe steam into hot water.  Two pipe steam is bad enough.  One pipe?  Start in just one place: how do you get the plug out of the dead end of the radiator to hook up the hot water return?  Without cracking something?  Good luck.



There is no excuse -- other than the convenience of moving the steam main -- for converting a one pipe steam system which will do everything a hot water system will do with only minor repair costs -- you even have the boiler!!!  It doesn't pay, economically.



If the client is adamant -- hot water or else -- my recommendation is that business can't be that slow.  Walk away from it.

Rod

Steam Radiator to Hot Water?

I agree with Jamie. You're proposing to take an 89 year old radiators that have been running on less than 2 PSI steam (a gas) and changing them to hot water (a liquid) which will then run at a much higher pressure. The chance of leaks (and liability) is more headache than you  need.  You may also find that the steam radiators don't do the job very well as they were sized for 212 degree steam and not 180 degree hot water.

As for changing over one pipe steam to hotwater, the information in the following attachment might be useful to you if you decide to go ahead. I have no experience on how well they work.. The only place I've seen them used is on a single basement radiator running on a hot water leg off a steam boiler, In this case potential leaking or heating efficiency wasn't all that important.

- Rod

Charlie from wmass

The radiator in the fourth picture

IS NOT convertible to hot water even if it was not a very bad idea. The top is not connected across with nipples so there is not efficient way to bleed this radiator. Why not just fix the steam?

Steamhead

Good eye, Charlie

on those Smith rads, they used cast-in shields so you wouldn't see the bolts that hold them together. But some people think they will work with water, because they didn't look close enough.



If they're all that way- and they probably are- you can't use them with water. Fix the steam, it'll be much less trouble.

pipe4zen

Deaf ears

Thanks for your responses, I agree with all. I know some of the radiators are definately

not convertible, was not sure about the first two radiators in the pictures. Either way I told them to leave the steam. They want to eliminate all piping for head room, and move boiler.

Too sad.

I decided not to get involve with this one.

It will be funny once the other guy figures this out after he runs pex to the radiators and tries to get rid of the air out.

Steamhead

It's possible

to reroute the main so it won't be in the way. We've done it.



Also, if all radiator runouts pitch down from the main and are dripped right below the rad risers, you don't even need to pitch the main. The runouts will act as drains.



But it looks like this one will be a classic fiasco, since there are so many knuckleheads working against you.

RadicalRadiator

Faith

Jamie and Rod, have some faith. 

Convert and test. If they hold water at 55#, you can be quite confident they will stand up to 15psi in the new hw system. If they don't then move on to replacements The two five column units are convertable. The three column and 2 column are not.

One of my first jobs was for Harvard University working on 7 of these HBSmiths with the internal rod. With all humility, I am very familiar. Normal tapping, bottom in and bottom out or top and bottom (there is a 2" ornate top plug on the opposite end, not shown) will do.

Good luck.