Convert from Steam to Hot Water?

Bret

I have a two-pipe steam system serving 32 radiators and about 3500 square feet of living space. The system works OK, but is a bit slow heating the house when temperature drops on cold days. The steam traps and control valves need replacing to improve the system. Most of the radiators are built-in and getting to them will not be cheap. My steam boiler is quite old probably has a only few years left.

For residential applications, there are many more qualifed contractors serving hot water systems than steam. There also seems to be very little product development in the residential steam space relative to everything going on in hot water systems heating (and cooling).

The maintenance costs for a steam system appear to be higher than for hot water. I fear this will become more expensive as fewer quailified residential steam contractors will be available going forward. I also would expect that residential steam parts will be harder and harder to find as it will not be economical for manufactures to support the market.

I know hot water systems can freeze, while steam doesn't. It seems that there are various approaches to preventing the freezing.

I've read Dan's books and have a great appreciation for the history of steam. However, the complexity of the steam system and limited support resources cause concern.

Assuming I can afford the converstion, can anyone tell my why I should stay with steam?

Craig_2

IMHO

I see some flaws in your logic. If your boiler is quite old, why does that make you think it only has a few years left? Mine is 80 years old and I believe it can last another 80 years. Inefficient maybe and certainly there are other reasons to replace it, but it works and I think yours will keep working too.

Steam is simple. Far simpler than water IMO. It's pretty easy to get vents (don't know about traps) and I suspect the sources won't dry up in the next decade or two. So parts will be available.

To convert to water, you will need to get at EVERY radiator. If they're hard to get at for steam, they will be hard to get at for water.

Homeowners on this list, including myself, are improving they're steam systems with a few relatively simple actions (replacing vents, wrapping pipes, diagnosing problems) with expert advice. The cost of converting will pay for a LOT of improvements/repairs. If it ain't broken, don't fix it.

Now, having said that, if you ain't comfortable then you don't need any more reason than that.

-cf

Bob W._2

Conversion..

Gotta agree with Craig on this one. Steam is simple; even I can understand it. Part aren't a problem at present, especially with the internet. I suppose if there is absolutely no one who will do a replacement steam boiler in your area this could be the reason to convert. Otherwise the only down side I see to keeping steam is the cost of operation. It just isn't as efficient as a new hot water system. Since you are considering a conversion using the old system and radiation, it would be interesting to know what kind of effciency you could get by switching to HWH. Would there be a payback in less than, say, 20-30 years? Maybe, maybe not. In my house all the rads (1,079 sq. ft.) and piping would have to go, so the cost of a new system would be considerable, and the payback long. For now I am keeping steam. Time will tell.

Boilerpro

Hi,ya BobW...Boilerpro

How's that "undersized" boiler doing? Just looked at the numbers and it sounds like the boiler is fired just to radiation with no PU or piping factor. Keep us up to date as you make improvements. Yours is a great test peice for my ideas about sizing steam boilers closer to the actual load. Have a blessed Christmas!

Boilerpro

Unknown

I would say

If you cant find someone qualified to work on your steam system - which is becoming more common - I would convert to hot water . A steam boiler and system is only as good as the guy working on them . I agree steam is a simple system , but it would be simple for anyone who installs them over a period of years . Either way you go , youre gonna wind up needing access to the rads to take out those old traps . Boilerpro has some experience converting steam to hot water - hes got some good pics utilizing the existing header and using an 1/8 inch vent hole for the return piping . Maybe he can repost em . Where are you located , Brett ?

zeb_3

EDR

Another thing to consider is that STEAM will put out more heat in a given radiator than HOT WATER. Meaning if steam is not heating your radiators sufficiently hot water will not.

Boilerpro

I don't believe that's true...

215F steam and 215 F average water temp will give you the same output. It's the temperature of the radiator that matters, not what is heating it. Most steam systems run at 215, while the old standard for water was 170 to 180 due to older open systems and the need to prevent them from boiling. Many newer systems are running 220F water or higher becaue they are sealed and pressurized...which rasies teh boiling point of water. The water temperature all depends on how much heat you need and surface area of the heating units. The converted steam systems I've worked with have run from about 150F in the rads to 190F in the rads on the "design day".


Boilerpro

Boilerpro

Here you go, Ron and Brett

This was the one pipe part of this system, not the two pipe part. The whole system was converted. Have another really big systm converions I have looked at and will be putting together the proposal in January. This system needed about 190F water temps and this was with some of the radiation removed. I had another one pipe conversion, and that only ran about 140F on the design day.

Boilerpro

Frank Cheng

I would do the conversion and put in a good condensing boiler

But be prepared for some problems, such as leaky rusty part of pipes.

Put in some thermostatic radiator valves, and a outdoor reset control. You can have a very comfortable heating system.

Frank

Steamhead

Bret, as long as The Wall exists

there will be steam experts available. I don't see a problem there.

I have a feeling your 2-pipe system is actually Vapor. These were the Cadillac of heating in their day and can still hold their own. Do you know who made the system?

Replacement trap innards are available from Barnes & Jones, Hoffman and Tunstall. They maintain online catalogs so you can determine what parts you need. Again, no problems here. There's still a lot of steam and Vapor out there, and even a few contractors like us who will still install steam from scratch! Plenty of market to support.

The sluggishness you mention is probably a trap or air-vent problem. Either is easily fixed.

I guess you can tell I like steam and Vapor systems. If that were my house, I'd repair the Vapor system and install a new, efficient boiler.

Web sites:

www.barnesandjones.com (trap parts)

www.gorton-valves.com (real nice air vents)

www.hoffmanspecialty.com (trap parts and air vents)

www.tunstall-inc.com (trap parts and radiator shutoff valve repair- can also rebuild rad shutoff into thermostatic units)

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Bret

I'm not sure who built the system. The current boiler is a Peerless (412,500 BTU). The beleive the traps are Warren-Webster (I might have the name wrong).

My concern with maintenance is getting to the traps and valves which are built-in. I do not want to rip open the walls every 3-5 years to replace the traps. I suppose I could put the traps and controls in the basement. Guessing that that would cost a lost less than a hot water conversion.

By the way, I'm located in Norwalk, CT. I would entertain keeping the steam if I had confidence that a qualified contractor could work with me now and going forward.

Steamhead

Do they look

like this?

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Steamhead

Or

like this?

BTW- there are a lot of good steam man in New England. Go to the Find a Contractor page of this site and follow the instructions to locate one near you.

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Steamhead

And

anything like this Float Trap/Air Eliminator and Return Trap on your system?


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zeb_3

Boiler pro

Good point. I've never seen residential over 200 deg. Our ave design temp is usually 190.

Bob W._2

Merry Christmas Dave.

Boiler is fine. So are we. No plans to modify anything until we get the infiltration and insulation issues resolved. Have a good one.

Bob Bona_4

once

the nostalgia wears off, even this wethead feels that steam systems are not the answer for the society of 2003. I think Bret is right on the money with his assessment of his systems future. For most people of today, messing around with blowdowns, monitoring water levels, trying to win the ever present corrosion battle is not on their agenda, nor do they want it to be.

If the desire and money is there to convert, it makes sense to.

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Bob W._2

I don't disagree...

especially if you already have a two pipe system as this gentleman does. For us stuck with beautiful one pipe rads there is no "conversion" that I can see. Its tear out and replace. That may happen some day, but there is no payback in my lifetime.

Bret

Mark Bagdon

Steam vx Hot Water output

> 215F steam and 215 F average water temp will give

> you the same output. It's the temperature of the

> radiator that matters, not what is heating it.

> Most steam systems run at 215, while the old

> standard for water was 170 to 180 due to older

> open systems and the need to prevent them from

> boiling. Many newer systems are running 220F

> water or higher becaue they are sealed and

> pressurized...which rasies teh boiling point of

> water. The water temperature all depends on how

> much heat you need and surface area of the

> heating units. The converted steam systems I've

> worked with have run from about 150F in the rads

> to 190F in the rads on the "design day".

> Boilerpro

Mark Bagdon

Steam vs Hot Water output

That is not technically true. Steam condensing at 215 deg puts out more heat than water at 215, but probably not enough difference to worry about. The heat transfer coefficient of the condensing steam is higher. If you look at ratings of coils, you will see that this is true.

Mark Bagdon

Need to remove Thermostatic traps

To convert a two pipe system to HW with Trane B-1 thermostic traps, do you have to remove the trap or can you get enough water flow by just removing the trap bellows element?

Also, do the pumping costs amount to enough to influence the payback calculations?

Steamhead

You would have to

remove the trap elements and possibly drill out the seats so they won't restrict the flow.

You may also have to repipe the return to the boiler since it may not be big enough to handle the amount of water needed.

And the pressure will be about 24 times (assuming a 2-story building) that of the Trane Vapor system so that may result in leaks.

Can you tell I love old Vapor systems? They were the Cadillac of heating in their day, and are still some of the best out there.

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Boilerpro

Keep the steam....Eliminate the traps...

Thermostatic traps aren't always necessary for two pipe steam. Take a look at the orifice valve type systems (ie. Moline)....no traps at the rads. This may be something to pursue for your system....Look into converting it to an orifice system... You'll need to run a heat load on each room and find out the effective EDR of each heating unit (correcting for installation in a recess, etc) to see if you have adequate radiation. I believe for these systems you only use about 80% of each rad. May have to check main sizes too. Orifices instaled in each radiator valve meter steam to each rad and as long as the pressure is kept within the design requirements, the rad condenses all the steam before it can reach the return. Haven't tried this yet, but sure would like to!

Boilerpro

Roger Litman

Converting from steam

I would first get a good steam man in your area to get you system up to snuff and then ask him the implications of the conversion. If he can cure your existing problems, then your decision may be easier. If your home, as is usually the case, conforms to the architecture of the steam period, then I would leave it in. I might try more than one company and listen to each of them before making a choice. You should be able to tell the phonies from the men.

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Bret

Maintenance of a two-pipe steam system with built-in radiators

My concern with steam is the need to perform maintenance work on the built-in raditors. I understand steam traps need to be replaced every 3-5 years.

If I can implement a solution that does not require access to the radiators for maintenance and I can fix some of the system's current inefficiencies, I might stay with steam.

Eliminating the steam traps and going with an orifice system sounds like one option.

I have also considered moving the steam traps and control valves to the basement near the mains.

What are the Wall's thoughts on the best design for the maintenance of a two-pipe steam system with built-in radiators?