From Steam to hot water radiators with zoning and new furnace, 70 year old boiler AL-PEX-AL

LS123

Hello All!

* This is my fist time on this site (and second post today), I can not find the first post to edit or delete, So I am re-posting in hopes of getting some feedback from you all.

First, I apologize if you find identical post without radiator and old furnace pictures, I hope that radiator pictures would help to get better feedback.

Currently we have steam boiler that is about 70 yeas old. We live in North East Connecticut (it gets pretty cold and windy some days and), we spend lots of money on oil. We would like to convert to water radiator system for few reasons. 1) Steam boiler use more oil to build steam, 2) with Steam heat we cannot use Zone heating, 3) Steam boiler is so old and in efficient and not helping the home value.

(furnace pictures are attached to show you how old it is. It must have been a coal burning boiler converted to oil. Distance between oil fire to the boiler is about 3 feet )

I have found a oil based furnace ( that would be able to heat the radiators with hot water.) Furnace is Burnham MPO-IQ147-TB (112,000 BTU Output Oil Fired High Efficiency 3-Pass Boiler), with direct venting and runs about 87% efficiently, per Burnham documentation. New furnace will be installed by a licensed professional, and he or she will connect 2 main pipes and circulator, Zone wiring etc.

Below are my questions:

1) based on what I was able to find on the web, I can convert the radiators from steam to hot water. with some modifications (such as removing and plugging the steam radiators air vents, and all the radiator heaters have screws on place to add bleed valves, and I will have to run all the return pipes from each radiator)

* Please note that Radiator1 intake side or return side is not reinforced like the radiator 2 intake or return side. (highlighted with arrow, -->picture "R2ReturnSide") So I am working with two different types of radiators. I know for sure "Radiator type 2 " definitely can be converted to hot water. I am not confident about the "radiator type 1"

What else can I do to be 100% certain that, I can convert both types of radiators to hot water radiators?

2) I intend to remove bunch of large metal pipes (almost all, all over the basement) and replace with AL-PEX-AL pipes connecting to the radiators. What size pex tubes should I use to feed the radiator with hot water, and what size pipes should I use for return hot water from each radiator (please note, pipes I am referring to in this question are going to the radiators from each Zone Valves)

3) what is the best practice? do you install the Zone valves on feeding side or return side?

4) The way I have seen so far one large pipe from furnace connect to the zoning pipes. Assuming I use Zone heat (with smaller pipes, Intend to have zoning for three floors) what size copper pipe should I use to feed hot water from the furnace to the Zone pipes? What size copper pipe should I use for all the return zone pipes to connect to the furnace?

5) Having the furnace installed, circulator pump installed (circulator pump that is suitable for three floors. including the basement.) and connecting the 2 main pipes to the furnace by a professional.
Would it be best,and safe to have water pressure to be about 20 PSI, and about 180 Fahrenheit (I will be using best AL-PEX-AL pipes for this project?

6) We have a brick chimney that is currently being used by the old steam furnace. The new furnace has capability of using direct vent. Should it best to use the direct vent option? How much would it cost to have direct venting to be installed? or is it best to use the existing chimney?

Please help me out with the information, , I have not been able to find out on the web yet, thank you all in advance!!

LS

EBEBRATT-Ed

First things first.
1. you need to know how much heat your house needs. Your contractor should do this. You can do your own to check his numbers by downloading the "Slant Finn" app.
2. Once you get the heat loss then you need to add up all your radiators btu rating to find out if they are large enough.
3. you will get less BTUs out of the same radiators on hot water than on steam but older steam systems were over sized so you may be ok.

If you wan't the job to work you have to start with these 3 steps then come back here.

Jamie Hall

Well, that boiler surely has done its time -- and it needs replacement. That said, allow me to address some of your thinking and questions.

First, and perhaps most important, you state "Steam boiler use more oil to build steam". This simply isn't true. With the exception of what are called mod/con boilers, which it is unlikely that you can use, a steam boiler and a hot water boiler will be within a percentage point or two of the each other with regards to the amount of usable heat transferred to the structure -- which is, of course, the objective of the exercise.

So we can get rid of that one right away.

Second, you state "Steam boiler is so old and in efficient and not helping the home value". Quite true. It's high time it was replaced. You could replace, so far as the boiler is concerned, with either steam or hot water for very nearly the same cost.

Your third point -- that you can zone hot water -- is mostly true and is, in my mind, one of the very few advantages of hot water heat.

Now on to a few other considerations.

First, your first real question appears to be can you convert the radiators. Probably. But before you do, you will need to pressure test them. Keep in mind that you will be running 15 to 20 psi water instead of 1 psi steam. There is no guarantee that they won't leak under the higher pressure. So pressure test each one separately. What you are referring to as "reinforcing" rods on radiator type 2 are there solely to keep the sections together. They are not reinforcements in any traditional sense -- that is, they won't withstand significant tension. They are there in the other type of radiator too, but are concealed inside. Don't even try to take up on them to fix a leak. It won't work, and you'll break them.

The second question refers to using pex-Al-pex. This may not be feasible, however, to see why we need to digress.

If you are putting in a hot water system, the first thing -- the very first thing -- is to calculate the heat loss of the house. Unlike steam boilers, which are matched to the radiation, hot water boilers are matched to the building heat loss. You can't go by what's already there. Since you seem to have already picked your boiler, I hope that you have done this step -- otherwise, bluntly, you're doomed to severe disappointment -- and high fuel bills.

Second, having calculated the heat loss of the building and each room, you need to determine at what temperature the system will need to operate to give you the needed heat. This should be done room by room. The heat output of a radiator is related to two things: the temperature of the heating medium (215 for steam) and the effective area of the radiator, or "EDR". A radiator operating on steam puts out about 240 BTUh per square foot of EDR. For hot water, the heat output drops with decreasing water temperature; to a very close approximation, about 1.7 BTUh per degree temperature below 215. So, for example, a hot water radiator on 180 degree water will only put out about three quarters as much heat as the same radiator running on steam. Using this relationship, you can determine by your radiator sizes and the heat loss of each room what water temperature is needed -- or indeed whether your radiators are even big enough.

Which brings us back to pipe choice. I personally would not use pex-Al-pex for water temperatures over 150, even though it is rated higher, unless all the pipe is run in troughs. It sags. I would use copper. The pipe size is determined by the BTUh rating of the radiators which it is feeding.

In your item 4, you question the location of zone valves and pump. It's not so simple. The best practice is to use primary/secondary piping. Particularly with zoned systems, direct circulation can give rise to some serious cycling problems for the boiler, and as you will be disappointed by the system performance -- and the high fuel bills. In primary/secondary, there is one circuit which runs from the boiler through a manifold and back to the boiler. The other circuit takes off from that, either with individual zone pumps or with a single circulating pump, usually a delta P controlled ECM pump, and zone valves. The zone valves can be either on the feed side or the return side.

Item 5 refers to sizing the circulating pump. It is sized based on flow and the pressure drop in the circuit, not the height of the building. Cold static system pressure is based on building height, and 20 psi should be adequate.

Item 6 you refer to using the existing chimney or direct vent. My answer to that would depend entirely on the condition of the existing chimney. It it's in good shape, I'd use it and save the expense and headache of direct vent. Otherwise, it is likely to be less expensive to install direct vent if the boiler permits it.

So much for your questions.

All that said, I cannot and never do recommend converting a functioning steam system to hot water. You will not save on fuel, and the conversion will cost you more than having a modern steam boiler installed properly by a substantial margin -- and that is a cost you will never recover. The only -- and may I stress ONLY -- advantage of a hot water conversion is the ability to easily zone the system.

Steamhead

That's a LOT more work- and money spent- than is needed to increase your system's efficiency. I certainly hope you haven't begun demolition.

Much of your system's inefficiency comes from the boiler. It's an old "all-fuel" type with a lot of mass, and the wide flueways are not baffled to increase heat transfer. So a lot of heat is going straight up the chimney without touching the cast-iron. I'll bet it has to run for a while- 15-20 minutes, maybe- before it starts to make steam. At least it has a modern burner, though all that soot indicates poor combustion.

In the World War 2 years when fuel was rationed, it was common to use bricks or various forms of metal baffles in these boilers to make the hot flue gases wipe the cast-iron better, thereby using less oil. That's one thing that helped us win that war.

A modern oil-fired boiler would not only have less mass, but more-extensive heat-transfer surface. Since you mentioned the Burnham MPO series, with its 87% AFUE, it makes sense to also look at its steam cousin, the MegaSteam. This is hands down the best oil-fired residential steamer out there, with the best warranty in the business and an AFUE of 86%. When we replace old all-fuel boilers with MegaSteams, our customers report substantially reduced fuel consumption.

So much for the boiler. Turning to the steam distribution system, I'm willing to bet it could do better. Look at our Find a Contractor ad, linked below- we cut that building's fuel consumption by a third, without replacing the boilers or converting to hot-water. The main thing was to get the air out of the steam pipes quickly on each cycle. For this we added a LOT of main vents. Re-tuning the burners and upgrading the outdoor reset control completed the work. The pipes were already insulated before we got involved- not sure how much they saved when that was done.

There are those who insist that the only thing to do with a steam system is to kill it. I haven't seen a single solitary instance of this where the person so stating didn't have an agenda. The following thread is one example:

https://forum.heatinghelp.com/discussion/145002/actual-savings-over-steam-heating

Now, to answer your question: Yes, those radiators were designed so they will work on a hot-water system, as well as steam. However, for a given radiator size, they will only give off roughly 2/3 the amount of heat on hot-water as on steam. So the house may not heat well.

Second, a one-pipe steam system should circulate steam on ounces instead of pounds of pressure. Proper venting is one thing that makes this possible. You are correct that a hot-water system in a 3-story house would run roughly 20 PSI. This increased pressure will do a great job of finding any weak points in the radiators and piping. They'll show up as leaks.

Third, installing thermostatic radiator vents will give you room-by-room zoning. Install them in rooms you want to run cooler than the rest of the house, such as guest rooms or bedrooms.

Fourth, since a steam system drains almost completely dry when it shuts off, there's much, much less danger of freezing pipes and radiators during an extended power or fuel failure.

Fifth, if you have your heart set on direct venting, you can use an approved power-venter with a MegaSteam. I don't recommend going this way, since this adds moving parts which can break down. Re-lining the chimney is a much more reliable solution.

Bottom line is, you can get pretty much the same result by going to a modern steam boiler and optimizing the rest of the system. Why do all that work when it's not needed for the results you want?

HVACNUT

Disclaimer:
I must make it clear that I do not condone your behavior, and the (limited) information I have is given under duress. I would never ever convert a beautiful steam heat system to anything but more of the same. You mentioned Burnham so I'm sure you looked at their MegaSteam boiler.

Responses might be slow as some regulars probably threw their phone at the wall or smashed their monitor after reading your title.

IF, IF, I was to know someone who knows a guy who's sisters boyfriend did it, he might have used one perimeter loop with a Delta T pump, TRV's and constant circulation.

I dont see how steam heat would adversely affect home value in the negative. People who have known steam heat would probably pay more. It's part of the home and its history.

And if you convert, there are boilers waaaaay better than the MPO. IMO.

LS123

Dear Jamie Hall, and EBEBRATT-Ed,

I cannot thank you enough both of you providing me with so much valuable, educational information. Last few days I have been trying to find some info but was not very successful, until I received your feedback. I feel like I hit the jackpot! I post my questions about 7 pm today and received wealth of knowledge less than two hours. Impressive! is an understatement.

I forgot to add that to my original post, I also plan to put a Wood Stove (Regency F5200 (covers over 3000 SQ) , one of the largest wood stove that has 4.42 cubic feet fire box (90 lbs max wood load, with Catalyst (10 year warranty), efficiency 85%, and slow burn up to 30 hours, I will be happy to load it once or twice a day.

Initially I had several contractor came over and calculated the heat loss and recommended Steam boiler (Mega Steam model MST513 ) with 123,000 BTU 513 Sq. Ft. Steam Boiler w/o Tankless Coil (Oil), with 86% efficiency.

I just looked up Mod/Con steam and impressed by 98% efficiency.

I am the only person living in 2500 SQ house. I stay in the main floor. Bedrooms, bathroom on the second floor are being used on ly couple of weekends a month by my children. So mostly completed basement and second floor is not being utilized daily, and I am heating areas I seldomly use. That is why I was thinking that if I zone it, I can keep second floor and basement about 55 degrees, save money, and keep less of a carbon foot print.

Additionally some Steam pipe are in the basement and not the best thing to look at, then again I don't use the basement. Pipes are about six and half above from the basement floor. So they are above average person's height

I will use the existing chimney, and I will most likely come back with more questions in Spring when I don't have to use the furnace. Then I can do pressure tests, more planing, etc.

I thank you again for this comprehensive information, and quick responses.

Most sincerely,
LS

LS123

Dear Steamhead,

LOL, Its still cold and snow in Connecticut. I have not taken the radiators out. The radiator pictures without connecting to the steam was in the attic, and not being used.

I am going to research thermostatic radiator vents, if there is a less expensive way to keep the heat down on the second floor and basement I would be very happy.

You are absolutely correct about the Mega Steam product line, they produce 99% steam and much more effective. That was recommended by couple of consultants that came to see the system for upgrade estimate.

You also have good point about hot water radiator system, if I convert to hot water could end up costing me so much more, if the system start leaking water, bursting pipes due increase pressure. I have no doubt that had I put a hot water system most likely it would have many failing points.

I didn't know that direct vent has moving parts, less parts are better less points of failures.

I agree that burner is not working well and producing soot and based on this old steam boiler, yes most heat go out of the chimney.

I was wondering what else I can do to optimize rest of the system?

Thank you for providing me with this valuable information. Without all of your feedback, I was heading toward very expensive project.

So it seems to me based on yours and Jamie Hall information, now I only need to get the MegaSteam boiler. you have stoped me from shooting my own foot, or digging a whole deeper than I could get out of.

Many thanks Steamhead!
\-LS

LS123

Daer HVACNUT,

You are supper funny. I hope my title did not damage too may phones or other electronic communication devices.

You are the third person that have recommended keeping the Steam heating system. Based on three of your feed back I am replacing the old boiler with new Mega Steam

I mean current Steam Boiler is so out dated, that keeps the home value down. I understand by replacing old furnace with a new one can increase home value by max 5%.

I Know the person you know, that know someone who knows a guy who's sister's boyfriend did it too:
-->"one perimeter loop with a Delta T pump, TRV's and constant circulation" is that something that can be done to Steam heating system?"

I am new to this project and just wanted to get clarification on that.

Please thank the person you know, that I know now,that know someone who knows a guy who's sister's boyfriend did it too....

I love the humor!

Thank you again for this information. All of you feedbak save me from making a huge mistake.

Best regards Hvacnut!! Really appreciate all of your feedback!

Steamhead

LS123 said:

Dear Steamhead,

LOL, Its still cold and snow in Connecticut. I have not taken the radiators out. The radiator pictures without connecting to the steam was in the attic, and not being used.

I am going to research thermostatic radiator vents, if there is a less expensive way to keep the heat down on the second floor and basement I would be very happy.

You are absolutely correct about the Mega Steam product line, they produce 99% steam and much more effective. That was recommended by couple of consultants that came to see the system for upgrade estimate.

You also have good point about hot water radiator system, if I convert to hot water could end up costing me so much more, if the system start leaking water, bursting pipes due increase pressure. I have no doubt that had I put a hot water system most likely it would have many failing points.

I didn't know that direct vent has moving parts, less parts are better less points of failures.

I agree that burner is not working well and producing soot and based on this old steam boiler, yes most heat go out of the chimney.

I was wondering what else I can do to optimize rest of the system?

Thank you for providing me with this valuable information. Without all of your feedback, I was heading toward very expensive project.

So it seems to me based on yours and Jamie Hall information, now I only need to get the MegaSteam boiler. you have stoped me from shooting my own foot, or digging a whole deeper than I could get out of.

Many thanks Steamhead!
\-LS

No problem, that's why we're here.

This is the thermostatic radiator vent to use:

https://assets.danfoss.com/documents/DOC200586466852/DOC200586466852.pdf

LS123

Thank you SO very Steamhead!

HVACNUT

Constant circulation would be used if you converted from steam to hot water.
(If I knew how, this is where I would put the Greta Thunberg "How DARE You!" meme)

The link provided by @Steamhead is what you want for room by room temperature control.

So,
Burnham Mega Steam.
TRV's.
Upgrade/replace main and rad vents.
What else?

Get info from the Gents here on correct steam boiler piping. It's extremely important the contractor knows how to read an installation manual. Even looking at the pictures is a plus. Will the contractor use the Drop Header design? Vaporstat? Things to ask.

A direct vent flue is not necessarily a power vent. Depending upon manufacturer and burner, a sidewall direct vent, without power assist is a better option. But what's wrong with the chimney?

No heat loss calculation on a steam system. A measurement of all the rads and connected steam piping is needed. The Pros here can help you with that as I here boiler EDR ratings are very conservative.
The burner plays a role here as well, as one manufacturer may be able to achieve a firing rate that another cannot.

What type of water heater is that?
Maybe have the contractor pipe in for a future indirect water heater.

Is it an exterior chimney?
Is there a stainless steel liner?

Now is also the time to abate the buried oil line and run a new line complete, from tank to burner. With all the necessary goodies in between. We can help with that as well.

Jamie Hall

And while we are al at it, see if you can get in touch with @Charlie from wmass (Charles Garrity) -- he's in the "Find a Contractor" link. One of the best steam guys around, and works out of Springfield, MA, but I know he works in Connecticut.

pecmsg

Do you really think when your all done converting to HW that you will save anywhere near the 15, 20K + spent in the life of the equipment?

Want to reduce your heating bill...……….tighten the envelope! Windows, doors, spray foam the attic, wall and floor insulation.
That is the best return on investment you can make. Once tightened that antique can be replaced with a much smaller more fuel efficient model.

The house heat loss will have to be recalculated and radiators MAY have to be downsized but still much cheaper then ripping everything out and full replacement.

LS123

Good morning HVACNUT, Jamie Hall, HVACNUT ! I am going to re-read all the info you all provided, and I already know I will many questions and provide you with additional details.
I thank you all wholeheartedly!
Best!
\-LS

Steamhead

Jamie Hall said:

And while we are al at it, see if you can get in touch with @Charlie from wmass (Charles Garrity) -- he's in the "Find a Contractor" link. One of the best steam guys around, and works out of Springfield, MA, but I know he works in Connecticut.

This!

nicholas bonham-carter

A very handsome boiler!
I would contact Charles Garrity, and get any main venting problems identified, and maybe corrected. He may have advice about other improvements to the system, (baffling the firebox, installing a low pressure gauge, Checking the location, and operation of the thermostat, etc.) , which could improve the system efficiency, while you are saving money for the replacement.
Tightening up the house against the cold wind is always a wise move.--NBC

LS123

Hello everyone.

Sorry I couldn't get back to you all yesterday, was not feeling well.

So based on all of your feedback, I have decided to keep the steam radiator heating system. Most new steam oil furnace, it self are at high efficiency ( max 86% I have seen is Mega Steam which I really like.)

I will assign a number to each one of my questions.

price of $69.00 --
Honeywell HR90TheraPro Digital Radiator Controller

https://forwardthinking.honeywellhome.com/related_links/water/therapro/install/Owners_Guide.pdf

Or
price of $38.00 Honeywell T104A Thermostatic Control

https://forwardthinking.honeywellhome.com/related_links/water/thermostatic_radiator_valve/install/62_3046.pdf

Q-1) Two steam radiator controls above, I am not sure if I should go with digital, or not so digital.

The two the controllers I have selected out of so many controllers, but if any one of you have any recommendations let me know. I kind of like the fact I could adjust the temperature to exact temperature for each room. For example, my daughter prefers her room temperature about 68 degrees, and my son would prefers his room to be about 75 Degrees. With digital control they can be comfortable and change temp as they would like.

I also discovered that there are steam air vents that can be adjusted to slow the amount of air being pushed out of the radiators.

Q-2) Can I use both adjustable air vents and Thermostatic Control on some radiators?

I plan to install a wood burning stove on the main floor, there is a good circulation on the main floor, for an example you can walk in a circle to reach each room when the doors are open ?

Q-2A) Should I just use the cheaper option, controllable air vents to reduce the amount of air being pushed out the the main floor radiators?

Q-2B) Do Thermostatic Control devices allow me to prevent any steam going in to the rad, like its totally closed and no steam can get to the radiator?

* During boiler replacement, I will get all the air vents, including main vent replaced with new once. By the way it takes about 15 to 20 minutes for the radiators to start making hissing noise, I rarely see / hear the main air vent push out steam.

Q-3) Is that normal or it to take 20 minutes to take push out air and air vents to start making that hissing noise?

* I can use the existing chimney, it is fine, and it needs cleaning and I plan to install stainless chimney liner to protect the brick chimney we have.

* I do not know what will it be, Drop Header design or Vaporstat. I am assuming this depend on the Mega Steam, or any other top rated steam boiler that will be installed.

* Yes I agree, and I would prefer to have a indirect water heater that would connect to the boiler, in the future. (main reason I would like indirect water heater because, if there is an extended power outage, the generator I plan to get could power the boiler (and indirect water heater), water pump (we have a well water system) refrigerator and couple of lights.

* Yes, It is best to put a new oil line from the tank to the new furnace. Oil talk is about 6 feet away from the boiler and it is in the basement.

* We plan to put insulation between R35-R49 on the attic. Unfortunately, this house is so old, and there are no insulation between the out side and inside walls. (I was informed that form insulation can be used should I move forward with that (that is another project)

* While cleaning the garage while back, I found a oil burner in a box with documentations that belong to it. It appears to be new to one, but has a label referring to 2008. It says on the burner's Firing Range 0.5 - 2.25 GPH. on another place it is referring to 3 gph and 2 gph Pictures attached.) I don't mind paying for one of the best burners, but if this burner I have can reach efficiency of a new burners then perhaps I could use it on the new furnace (if the furnace comes without a burner)

Q-4) Do you know if mega steam Or any other top rated furnaces come with or without a burners?

* Thank you for providing me with a well experienced professional specialized in steam heating systems, I intend to contact @Charlie from wmass (Charles Garrity)

I will send you a diagram of pipes, size of each pipe tomorrow.

Thanks!
\-LS








with its own oil burner?

Jamie Hall

OK. Start at the top here. Neither of those controls which you have called out are intended for steam. They are for hot water systems, and only certain ones at that. There are, however, thermostatically controlled radiator vents which can be used to limit the output of the radiator if the space is too warm. The best procedure is to get all the venting -- especially the main, but also the radiators -- adjusted so that the spaces are as desired, then if you need to reduce the temperature in a specific room you can use a thermostatically controlled vent to do so.

If it takes 20 minutes to get steam to a radiator vent, the chances are very good indeed that the main venting -- not the radiator venting -- is too small. This will need to be corrected.

Now. There may be a problem. I can't speak for Charles, although I regard him as a friend, but I would be rather surprised if he were happy with picking up partway through what sounds like a do-it-yourself job. Most contactors I know are not willing to do that, for good reason: they wind up being responsible for work someone else did, and that's not a good position to be in. I would very much recommend that the contractor whom you hire be in charge of selecting and purchasing the boiler, determining whether or not it needs a drop header (one never hurts!) and the correct pressure control; one pipe steam can usually work quite happily with a pressuretrol, and installing the boiler, assembling the piping and controls, hooking up the oil tank -- and all that -- and commissioning and adjusting the new boiler.

With regard to the oil burner. The new boiler will come with a new oil burner, which the contractor will have chosen to match the boiler. These things are not plug and play.

LS123

Hello Jamie Hall,

I am not planing to install the new furnace myself,

In addition to what you mention of how contractors would not like to finish someone else work and be held responsible.

I do not have the full knowledge, nor tools needed to do a big job like this.

Had I not reach out to the steam system experience individual like you and others, who have been providing me with valuable information, I would have paid someone to change from steam to water. It would have cost me a lot of money, I mean lots of money. Especially if the water start leaking from pipe and radiators because of high pressure hot water heating system need.

I will be contacting Charles next week and I would have Charles Garrity give me an estimate on installing the new furnace and anything else he can do to improve the heating system.

Information all of you provided this far has been educational. I am in general like to know and learn about anything new, especially home improvement project.

Thank you!
\-LS

LS123

Hello All,

This discussion will be closed at my request by the administrator.

Having all of your contributions helped me save a lots of money, by staying with oil steam boiler. Had I converted my system, I would have been in big trouble and would have spend a lot with hot water boiler, pipes, radiators. I learned from you all that Steam boiler run at 1 psi. water boiler would be at 20-25 psi. So the water could have leaked from the 70 year old pipes and radiators, run return pipes to the boiler, etc.

So I am staying with oil steam, and getting Mega Steam Boiler

Thanks again.

\-LS

pecmsg

Two thumbs up.