Steam to Hot Water Conversion

Michele

The original two pipe steam boiler in my home(4700 sq ft excluding full basement, built in 1922)is about to give out after 80+ years of loyal service. It is now sending more steam up the flue than gets to the radiators and my heat bills have doubled over last year's. Because I had been having a difficult time getting heat through all my radiators evenly (even before a boiler leak became evident), I am considering a contractor's suggestion to convert my steam system to hot water. I like the idea of being able to control the water temp (vs. 212 deg steam, either on or off) and feel that the hot water system will provide more even heat. This contractor has converted aproximately 15 systems over the last few years in houses like mine. He is confident that leaks through out the system won't be an issue, but it worries me nonetheless. Does anybody have any experience with such conversions? Or should I just replace steam with steam and hope the radiator problems go away with the increased steam pressure of the new boiler? Any help would be appreciated....

Steamhead

That's probably a Vapor system

which was the Cadillac of heating in its day, and is still one of the best out there. Assuming it's in good repair and the boilers are similar, a steam or Vapor system can approach the efficiency of hot water. The difference is that in steam or Vapor, you vary the quantity of steam. This is similar to varying water temperature in a hot-water system.

I like these systems. They run at about a tenth of the pressure of hot-water, and they won't freeze up during power failures like hot-water can. When installed and maintained properly, they are quick, quiet and efficient.

There are quite a few pitfalls when doing such a conversion. Dan addresses them in this article: http://www.heatinghelp.com/newsletter.cfm?Id=22

If that were my system, I'd install a modern, efficient steam boiler. Then I'd make sure all the vents and traps (if used) were in good shape and properly sized. If you go this way, you'll have a great system that will last for many more years.



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[Deleted User]

I agree w/

Steamhead. Find a contractor who knows how old systems are supposed to work. He does not have to be old. However, a good sign would be for him to show up wearing a Deadman's hat or tee shirt. If he is really good, he will bring a blue book w/ pictures and descriptions of how the old systems were installed and how they operate.

Then he will install a new, efficient boiler. And. To show you that he is a real professional, he will explain how you can heat your 4,700 sq. ft. mansion w/ less than 1 pound of pressure. Maybe only a few ounces.

Happy vapor heating.

Craig_2

Speaking as a homeowner

You need a new boiler ether way so you have that expense. Converting to hot water will also require all new return piping. A new steam boiler will not increase the pressure. Steam systems run on very, very little pressure. High pressure WILL cause problems. In my opinion, you would be best served by reading about your steam system before making your decision. The Lost Art of Steam Heating by Dan Holohan is easy reading. Although the contractor may be quite capable of what he is proposing, remember he is SELLING to you. It's in his interest for you to spend more. Educate yourself about wht you have and you will feel more confident whether you convert or not.
Good luck.

-cf

David Shapiro

follow up to question about steam to hot water conversion

If I have a steam boiler, it seems from what I am reading that there is no reason to convert to hot water, as long as the contractor is knowledgable, is that a correct statement of what I am reading? Or is there a good reason to convert from steam to hot water? Thank you! David

steve_6

reason

Their is no good reason to convert from steam to hot water. Contractors who try to get you to convert, usually dont know steam systems, especially vapor systems.
All you need is a new boiler with a tune up on your system.

David Shapiro

radiator to baseboard conversion

on the same line of reasoning, I suspect there is no reason to convert from radiator to baseboard either, as long as the radiators are working ok and kept up? (I am not knowledgable about these issues, so really appreciate your input).

Steamhead

Radiators vs. Baseboard

The cast-iron radiator is one of the best things ever invented to heat a building with. It gets its name from the fact that part of the heat it gives off is "radiated" much the same as the heat from the sun shines on you. Air passing over the radiator is also heated by convection, where warmer air rises and pulls cooler air over the radiator. Also, cast-iron holds its heat when the water or steam shuts off.

Most baseboard, on the other hand, works by convection only. There is little if any radiation from one of these units, which IMHO detracts from comfort. Baseboard also cools quickly when the system shuts off.

Baseboard has the advantage that it takes up much less space than cast-iron radiators do. But I think the increased comfort justifies the space radiators take up.

If space is a problem, several manufacturers make cast-iron baseboard which works almost as well as radiators do. It costs more than the usual fin-tube baseboard, but is worth it.

If you have a steam or hot-water system with radiators, I would simply fix any problems and let it run another 80 years.

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[Deleted User]

I would like to elaborate on

what my knowledgeable friend from snowed in Baltimore said.

Unless your better half is complaining about how those ugly radiators don't match her new decor - keep them. Those beautiful cast iron hunks contain lots of square feet of heating surface. You might have to add on to the house to install enough baseboard. And. Just think of tearing up floors to move the pipes.

I have seen steam to water conversions. Some good. Some not so good. The complaint most often heard, even on the good ones, is "I'm just not as warm as I used to be." So hang onto your steam as long as you can. You'll be the warmer for it.

Steamhead

And (thanks, Ron)

if the existing radiators really are in the way, you can still get cast-iron radiators in different shapes and sizes. These can be made to go where needed, same as the original ones were.

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Michele

Thank you all so much for your insights.....I will get Dan's book as suggested and will probe my contractor further with respect to steam and a tune-up on all the radiators not seeming to work. But as far as my steam system goes, we do feel like it is only easy to keep warm in our house in the coldest months...that is why I am tempted by the hot water conversion. I really hate the thought of replacing my boiler - mostly because I hate the thought of loosing such a beautiful piece of machinery and history (the existing boiler is about 6'x6'x5' and beautiful!) Our architect was a famous turn of the century German born who built a number of the area' landmarks in Detroit's boom days. I will likely leave the old boiler where it is and put the new nearby. Thanks for all your help.....
Michele

Michele

Thank you! I just printed out Dan's article you suggested and will review it with my contractor......how lucky I am to come across this forum with so many who seem so willing to help! Wish me luck. Never thought I would learn so much when we bought this big old house!
Michele

Steamhead

If you're having trouble

geting the house warm, you may have a bad trap or an air-venting problem. These are really easy to fix, and cost far less than converting to hot-water.

You may want to go to the "Find a Contractor" page of this site to locate someone near you who can give you a second opinion. Too bad you're not in the Baltimore area- I'd love to get my hands on your system!

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Michele

Thanks SteamHead....I wish you lived nearby too. I did check out the contractor's section and only one is listed nearby.....I am not sure how long he has been in business. The two contractors I have worked with do most of the larger old boiler systems in my area.....family businesses that were started in the 20's and 30's in our area. Hopefully they will be able to address some of the issues recommended to me in these posts!
Michele

Michele

Can you recommend a good 'efficient' steam boiler brand? And when you recommend that traps be cleaned out and sized, do you mean each trap on each individual radiator or do you mean the main traps on the lines in the basement? Also, you mentioned that the quantity of steam can be varied like the temp of the hot water can be controlled. Is there any type of automatic control that can increase the amount of steam with the outside temp? Are there thermostats made just for boilers? In the 'warmer' months I find that the boiler kicks on, heats the radiators and as soon as the temp on the thermostat is reached, it shuts down. Seems that the radiators furthest from the boiler cool down much faster, and hence I get very uneven heat during these months. Thanks again for all your help!
Michele

Steamhead

Answers-

Any steam boiler made today must have an annual efficiency (AFUE, which is something like miles-per-gallon for a car) of at least 80%. I've seen steamers as high as 86%. There are very few really bad steam boilers out there- I like Burnham, Columbia and Slant/Fin but there are people who swear by Crown, Dunkirk, Peerless, Smith, Weil-McLain (made right over there in Michigan City, IN) and others.

What really matters with any boiler is how well it is installed. No boiler can be expected to perform well if the installer does a poor job. In steam, the piping around the boiler is crucial to good operation. The manufacturer provides a piping diagram which the installer must follow to the letter.

The fast-cooldown problem is probably caused by uninsulated steam pipes. Remember, steam is a gas that really wants to condense back into a liquid. But you want it to condense in the radiators, not the pipes. When steam condenses to water, it shrinks 1700 times. This can cause a vacuum in those uninsulated pipes which can pull steam out of the radiators.

The traps that generally need attention are the ones on the radiators. You can still get parts for almost any trap. If there are two big "traps" in the return lines near the boiler, one is probably a float trap/air eliminator. This is the main air vent for the entire system. The other is a return trap, which makes sure the water can return to the boiler no matter what the boiler's pressure. BTW, do you know who made the ones on your system?

Outdoor-reset controllers do exist for steam. But before investing in one, I'd straighten out the system. Most times this will solve the problems that made you think of outdoor-reset in the first place. A standard or suitable digital-programmable thermostat works quite well on the usual steam or Vapor system.

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Michele

Final (?) Decision

Ok, Steamhead, your responses (along with others on this topic) have definately steered me away from converting from steam to hot water. I will also use your manufacturer recommendations. I also ordered two of Dan's books so I will better understand my system. I am a mechanical engineer, but I guess I never paid attention in my heat flow classes!

I had another contractor in today to quote a replacement - he uses Dan's book as his bible which made me feel better. He has never done a steam to hot water conversion but feels pretty confident that once we have a new steam boiler in place he will be able to get the steam flowing properly to the areas of the house that presently do not get even heat. I am a little weary about correcting all my radiator problems though, because a prior owner had installed vents on the problem radiators. Leads me to believe this problem existed well before the crack in the boiler.

One of your comments stumped the contractor though....he seemed a bit puzzled when I told him you suggested that the 'temp' could be controlled by the quantity of the steam. Could you elaborate a bit on this?

As for the types of traps in my basement, I am not sure of the manufacturer. I will email you pictures of the trap area if you are interested. The last contractor I had out to try to improve my poor heat flow in certain rooms tied an air vent into the main trap to try to improve the steam flow (or water return, I am not sure which). Today's contractor told me it was a two way air vent, which he said was not right on my vacuum type system. He pointed another vent out to me (looked newer too) and told me that it was a vacuum vent.

Slowly but surely I am learning.....thanks, Michele.

Steamhead

Here are your pics, Michele

The boiler pic is first. That should be an Ideal "Type A Heat Machine". This was one of the best residential boilers of its day. Whoever built that system went first-class! The "Columbia" is the name of the gas conversion burner.

The new vent looks like a Gorton or Maid-o-Mist #1. I think that's a bit small for that system- my choice is the Gorton #2 which has four times the capacity of the #1.

The "trap area" shows a green vent which I think is a Hoffman #76. It looks like this is venting the steam main- I think a Gorton #2 is a better choice here too. But measure the length and diameter of the main first to be sure.

"Varying the quantity of steam" is simply a matter of how long the burner runs each cycle, in response to the thermostat.

www.gorton-valves.com


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