Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

STEAM TO HOT WATER CONVERSION (9-UNIT APT BLDG)

9 unit building currently with two-pipe steam (2" risers / 1" returns)

50% of radiation is slant fin 2" steel convectors. Remaining is 25% Gov-free radiators and 25% 3 column, 10 section radiators for total of 2,400 EDU. Radiators have Danfoss valves and traps.

Owner would like more control for each apartment (top/bottom are too cold and middle is too hot) and no more banging or annual steam maintenance.

Trying to determine if the system can accommodate a hot water conversion without replacing the returns with larger pipes. Anyone have success in this situation?



Comments

  • Steamhead
    Steamhead Member Posts: 15,329
    Well, to begin, you have other pitfalls besides the return line sizes:

    1- You need over 10 times the pressure for hot-water that you do with steam. If there are ANY weak points in the system, this much-higher pressure WILL find them. Your insurance company won't like having to pay out for the resulting building damage.

    2- A hot-water radiator can only put out 2/3 the heat that a steam one can. You may find the building doesn't heat well because of this.

    Sure, you can ramp up the temperature to partially compensate. But if you promised the owner that shiny new super-expensive mod-con boiler would save a lot of gas, you'll get a nasty surprise, because the boiler will run above its condensing range.

    This is fixable without converting it. Balancing a steam system is easy once you know what you're doing, and in many cases the same work will reduce the building's fuel consumption. Given that, there's no reason whatsoever to risk a conversion.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    KC_JonesChrisJttekushan_3
  • Jamie Hall
    Jamie Hall Member Posts: 18,907
    With two pipe steam it isn't difficult to give each apartment -- indeed, each room -- control of its own temperatures. Use TRVs on the inlets of each radiator. No problem.

    The banging is easily -- and cheaply -- fixed, although it takes some detective work.

    First, make sure your pressure is correct -- no more than 1.5 psi cutout at the boiler.

    Next, make sure all the traps are working. The outlet pipes may be warm -- may be very warm -- but they shouldn't be steam hot. A digital thermometer properly used is a big help, although the old hold the hand (or try to!) on the pipe works pretty well too.

    Then the hardest part -- trace all the pipes and make sure that there are no dips or sags where water can collect, and that all the piping can drain to either a wet return or to the boiler. That's where the banging is coming from. Fix any problems you have with that.

    Then find out if your venting is adequate; if you can tell us what vents you have and where, and what the main piping sizes and layout is, we can help you there.

    At this point you will have spent some money. At a rough estimate, perhaps five percent (counting all the TRVs) of what a hot water boiler and conversion would have cost you. You will have a system which does what your owner wants it to do in terms of control and comfort.

    Annual steam maintenance isn't much of a problem -- or shouldn't be. As far as maintaining the boiler goes, the only thing different from hot water systems is that you do need to check the water level from time to time, and you do need to blow down the low water cutout from time to time. The blow down takes about 10 minutes, a couple of times a month. If you have an automatic water feeder -- which I like, although you will find that there are differing opinions on that -- with a water meter, you need to check that to see what your usage is -- which takes a glance when you are blowing down the LWCO. If you don't have an automatic feeder, someone really should check the level daily, and I can see that that could be a headache.

    As far as fuel usage goes, it is true that a really well set up mod/con boiler uses less fuel than a regular hot water boiler or steam boiler. However, as Steamhead mentioned, in order for the mod/con to reach those efficiencies, it has to be running pretty cool water, and the radiation has to be increased to allow that.

    Bottom line -- fix up the steam system so it runs the way it is supposed to run, and you and the owner will both be happier, and the owner will be a good deal richer.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    vaporvacChrisJttekushan_3Zman
  • vaporvac
    vaporvac Member Posts: 1,520
    I'm assuming this references your other post for twinning boilers? Does the boiler need replacing or could it have a multi-stage burner attached? If it needs replacing, twinned boilers with HLH burner (which are availabel for TR60/70 will be a less expensive, SAFER and more comfortable heat. Even a single stage burner with twinned boilers gives excellent results. Plus, everything @Jamie Hall said above. :)
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
    ttekushan_3
  • Amen to the previous comments, and I must say that if the pressure were kept below a few ounces, you would not need the TRV's. This is assuming that the radiators had originally been properly sized, (most likely).
    Get the boiler pressure regulated to mere ounces, verified by a good low pressure gauge, (0-3 psi from valworx). Any sort of 2-pipe steam system is very negatively sensitive to high pressure.
    Check the traps, and especially the crossover traps, which will let the air out of the main trap, and you should have a perfect system. This is assuming the boiler is properly piped.
    Post some pictures, for all here to see, and there will be plenty of advice.-NBC
    ttekushan_3
  • JohnNY
    JohnNY Member Posts: 2,917
    I've done this successfully, but it's not the common outcome. It really has to be thought through for the reasons Steamhead explains.
    Contact John "JohnNY" Cataneo, Master Plumber for Consulting Work
    Or for plumbing in NYC or in NJ.

    Or take his class.
  • Henry
    Henry Member Posts: 995
    We do a steam to hot water conversion about one every two years or so mainly in churches and commercial buildings but also apartment buildings. We are presently converting a large temple that had half hot water and half steam to hot water (2 x Cleaver Brooks 2.1 million replaced by 3 HTP ModCon 500!). Regarding leaks, the large apartment block that we did 3 years ago, only had one pipe leak and it was in the basement. So don't worry about it. Cast radiators in the old days were grossly oversized. So don't worry about lower temperatures of a hot water system. You might have to drill and tap for air vents. You don't have to remove the traps, just the guts and seat. We do all the conversion with primary/secondary piping using mod/con boilers. We had two consecutive 20% colder (by degree/days) winters and the client claims 35% savings on his gas bill by volume consumed.
  • JohnNY
    JohnNY Member Posts: 2,917
    That's been my experience too. We adapted 4.5" (try to find that fitting!) steam piping mains to 2" copper, added Triangle Tube condensing boilers and pumped it properly through a low-loss header. To date, the system temperature has not called for more than 138°F water, and that was on a 6°f day, and fuel costs dropped more than ⅓ according to the building's Director.
    No engineer. Just good math and a good installation crew.
    Contact John "JohnNY" Cataneo, Master Plumber for Consulting Work
    Or for plumbing in NYC or in NJ.

    Or take his class.
  • ChrisJ
    ChrisJ Member Posts: 12,819
    JohnNY said:

    That's been my experience too. We adapted 4.5" (try to find that fitting!) steam piping mains to 2" copper, added Triangle Tube condensing boilers and pumped it properly through a low-loss header. To date, the system temperature has not called for more than 138°F water, and that was on a 6°f day, and fuel costs dropped more than ⅓ according to the building's Director.
    No engineer. Just good math and a good installation crew.

    What was wrong with the steam system before it was converted?

    I find it a bit hard to swallow that a properly working steam system will use 60%+ more than even the best hot water system.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    ttekushan_3jonny88
  • Steamhead
    Steamhead Member Posts: 15,329
    ChrisJ said:

    What was wrong with the steam system before it was converted?

    I find it a bit hard to swallow that a properly working steam system will use 60%+ more than even the best hot water system.

    Interesting how we never hear anything but that they converted a steam system to hot water and fuel consumption went down by roughly a third. I've put this question out there a bunch of times and have yet to hear an answer.

    But we have achieved similar savings by fixing the steam, with far less risk and at far less cost. Here's our most dramatic example, achieved without replacing the boilers:

    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc

    This topic seems like it belongs on "The Undead", or whatever they call this year's zombie show. Despite our being able to show similar savings, the convert-or-rip-out-all-steam-systems crowd keeps showing up. Here's a recent example:

    http://forum.heatinghelp.com/discussion/145002/actual-savings-over-steam-heating
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    KC_JonesChrisJttekushan_3
  • ttekushan_3
    ttekushan_3 Member Posts: 942
    I don't understand why anyone would want to do anything other than repair what's there. There's always room for interesting system tweaks that get great results.

    I typically get 30% reductions in fuel consumption per heating degree day. Best results were exceptional, in one instance 65% reduction and 70% in another. Though statistical outliers, each of these examples was 1. deemed hopeless and judged to require "conversion therapy" ;) and 2. brought under control with no major component changes: meaning that they were "unscrewed up" while retaining all major components and piping. These were single season payback periods.

    A recent sizable project is now using fuel at a rate of under 8 BTU/square foot/heating degree day without energy retrofit or major steam system component changes. Reduction is about 35%. It All comes down to correcting piping errors, balancing, modulation, replacing bad traps and tuning of heating cycles. Plus some tricks that no one seems interested in learning.

    In talking with @izhadano his vacuum system has taken a recalcitrant steam system from about 13.5 BTU/sf/HDD down to about 7.8 BTU/sf/HDD with no other conservation measures.

    Long and short of it is, a steam system (particularly large two pipe setups) will perform in a state of the art fashion under two conditions: 1. you are given the freedom to make it so and 2. are willing and capable of doing so.
    terry
    KC_Jones
  • ttekushan_3
    ttekushan_3 Member Posts: 942
    And one more thing. The owner doesn't want yearly maintenance? What on earth is he thinking will operate without yearly maintenance? Condensing boilers? Oh that'll turn out well.
    terry
    Canucker
  • OleTwoPiper
    OleTwoPiper Member Posts: 17
    All good points.
    In response to some of the questions as to why would anyone want to convert from steam to hot water (taking risk and spending $), there is a straightforward answer: Despite the participants in this forum being the most knowledgeable, interested, and experienced masters of steam heat around, the general population of heating professionals in the local area are not. And based on this fact, a heating company can send someone over to a building based on a resident complaint, and the junior technician automatically jacks up pressure and plays with the settings. Or, at the beginning of the season, even if the system is operating perfectly in the past, the heating company may not remember, or be called by ownership, to send a knowledgeable technician to check all traps, and even with boiler room settings correct, the whole system could be out of balance.
    Its as simple as that - hot water may be easier for less experienced people to operate, despite the benefits of keeping a properly tuned steam system in place.
    I'm not an advocate of the above per se, but just want to share an alternate point of view.
  • jonny88
    jonny88 Member Posts: 1,139
    Wholeheartedly disagree.Most buildings will have their own maintenance crew an example Riverside church in upper Manhattan,boiler room is incredible and all the crew working their are in charge of operating the steam fires boilers.We would service steam traps etc.In my experience apt buildings are run by educated Superintendents in aspects of plumbing and electric.They have the final say on who works in their building or at least request a crew that he/she likes.
    Your same theory about the junior mechanic going to a private residence applies to.If this is the case why don't we rip out all steam systems and put in hot water .Hot water systems today may be a lot more complicated then steam systems.
  • JohnNY
    JohnNY Member Posts: 2,917
    Steamhead said:



    Interesting how we never hear anything but that they converted a steam system to hot water and fuel consumption went down by roughly a third. I've put this question out there a bunch of times and have yet to hear an answer.

    What exactly is the question? Maybe I can answer it.

    Contact John "JohnNY" Cataneo, Master Plumber for Consulting Work
    Or for plumbing in NYC or in NJ.

    Or take his class.
  • BobC
    BobC Member Posts: 5,306
    Once a steam, system is operating correctly, little on this earth is as reliable. Replace the occasional air vent and keep the water at the right level and keep it clean. If it's two pipe, the steam traps have to be replaced occasionally. I've lived with steam heat for almost 70 years and the only thing that ever seemed to need fixing were the oil burners.

    Modcons and minisplits are wondrous things but they take a lot more maintenance than steam systems, especially if it's gas fired.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    ttekushan_3
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,564
    A couple of years ago, I toured a designers show house, whose entry fees benefited the Omaha Symphony.
    The steam heating system was still in place, but decommissioned, now replaced by high velocity forced air fed by geothermal heat pumps. The installing company made estimates of 60% savings, new vs, old, even though the new system had only been run a couple of weeks.
    Peering through the ornate fretwork radiator covers I saw marvelous lever valves with what seemed to be various graduations for regulating the steam.
    He might have been right about the savings, because when I got to the basement, the old boiler, still in place, had undersized supply pipes, and a pressuretrol set to 5 psi!--NBC
    ttekushan_3Zman
  • ChrisJ
    ChrisJ Member Posts: 12,819
    ChrisJ said:

    JohnNY said:

    That's been my experience too. We adapted 4.5" (try to find that fitting!) steam piping mains to 2" copper, added Triangle Tube condensing boilers and pumped it properly through a low-loss header. To date, the system temperature has not called for more than 138°F water, and that was on a 6°f day, and fuel costs dropped more than ⅓ according to the building's Director.
    No engineer. Just good math and a good installation crew.

    What was wrong with the steam system before it was converted?

    I find it a bit hard to swallow that a properly working steam system will use 60%+ more than even the best hot water system.
    JohnNY said:


    Steamhead said:



    Interesting how we never hear anything but that they converted a steam system to hot water and fuel consumption went down by roughly a third. I've put this question out there a bunch of times and have yet to hear an answer.

    What exactly is the question? Maybe I can answer it.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • ChrisJ
    ChrisJ Member Posts: 12,819
    edited October 2015
    My steam system costs me a few dollars per month less to run than our next door neighbor's 10+- year old forced hot air system.

    His house is smaller, has more insulation and fairly new windows. We both maintain the same setpoints. Houses are approximately the same age and I suspect even built by the same people.

    Yes, even with preheat times my system runs cheaper. Cheaper enough to make up for the 150 year old windows and lack of insulation and larger space.

    I'd be surprised if you could pull off a 10% savings with a modcon vs a properly operating steam system especially during a cold winter.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    jonny88ttekushan_3
  • SWEI
    SWEI Member Posts: 7,356
    It would be very challenging (but very interesting) to arrange a fair comparison. Properly operating, no, optimally operating is the tough part. It's relatively easy for a competent contractor to get a mod/con doing that.

    With vapor/vacuum, a modulating boiler, and orifices sized to the heat loss, I think you'd get close on steam. That combination is unfortunately about as rare as hen's teeth. We need to fix that.
  • justa1_visitor
    justa1_visitor Member Posts: 1
    OleTwoPiper said

    ....Despite the participants in this forum being the most knowledgeable, interested, and experienced masters of steam heat around, the general population of heating professionals in the local area are not....

    I'm an apt. bldg manager in Portland Maine and can attest to the lack of competent steam system help in the area. I've given up trying to find one that's working in any of the local plumbing/heating companies. After years of having problems with what was a new boiler, heating only 1 med. sized apt., I tried every co. in the area several times. Several people told me they "didn't know steam". I then asked specifically to send only people that did. Very sad results from that. At best, it didn't get worse. Many times, it did. Finally I got my retired father-in-law, 40 years heating experience, to come 300 miles to spend 90 minutes to get it running properly.
    I'm not talking details, I'm just trying to point out how steam heating systems will go the way of the dinosaurs if the installation and maintenance of them becomes a lost art. That loss seems to have already happened here in what was once a city heated predominantly by steam.
  • Abracadabra
    Abracadabra Member Posts: 1,948

    OleTwoPiper said

    ....Despite the participants in this forum being the most knowledgeable, interested, and experienced masters of steam heat around, the general population of heating professionals in the local area are not....

    I'm an apt. bldg manager in Portland Maine and can attest to the lack of competent steam system help in the area. I've given up trying to find one that's working in any of the local plumbing/heating companies. After years of having problems with what was a new boiler, heating only 1 med. sized apt., I tried every co. in the area several times. Several people told me they "didn't know steam". I then asked specifically to send only people that did. Very sad results from that. At best, it didn't get worse. Many times, it did. Finally I got my retired father-in-law, 40 years heating experience, to come 300 miles to spend 90 minutes to get it running properly.
    I'm not talking details, I'm just trying to point out how steam heating systems will go the way of the dinosaurs if the installation and maintenance of them becomes a lost art. That loss seems to have already happened here in what was once a city heated predominantly by steam.
    In Chicago metro area (I think currently the 3rd largest by population in the US) I can probably count on 2 hands the number of companies that are well known to work on steam systems. Out of those 10... oh.. let's call it 15... I've seen maybe 3 companies that can do steam properly. Everything from wrong near boiler piping to oversizing the boiler. Even things that you'd expect a heating company to be able to do for non-steam related jobs (ie. venting/gas line sizing) I've seen horrendous examples of work. Nearly every apartment building in the city built before 1960 still has steam, except for the ones that have been converted to condos. And let me tell you, that's A LOT of buildings and A LOT of boilers.

    This is exactly why when word gets around that you can do steam and do it properly you'll have no issues getting work. I have more work than I can deal with and I've been trying to get new guys but it's hard finding someone reliable and that's willing to learn.