Conversion of Steam system to Hot water system

randers2015

I am now leaning to convert steam system to hot water system. if anyone has personal experience to share about this conversion, would love to hear it.

KC_Jones

The first question, possibly for your education, why do you want to do this?

Labenaqui

Our experience has been limited to converting a qualified Steam Boiler to FHW only, not the complete radiator system, if that applies to your situation.
https://www.boilersondemand.com/steam/converting-a-steam-heating-system-to-hot-water-the-whys-and-hows/

AdmiralYoda

My first thought is that if you plan to run an atmospheric boiler I'm not sure you will gain anything as both steam and hot water are equally efficient. Second, an atmosphericly vented hot water boiler is going to have an operating temperature of 170-180 degrees so the radiators will be providing less btu's.

If you plan to use a condensing boiler those run at 140F or less and the radiators will definetely produce less heat.

You'd need a very good heat loss calculation of your house and rooms to determine if you would satisfy the design temp with the lower btu's of hot water filled radiators.

Lastly, you'll be going from 1.5psi or less to upwards of 25psi with hot water. Thats a quick way to find out if you have any leaks or areas that were getting ready to leak.

I'll 2nd @KC_Jones question. Why do you want to do this and what is your goal?

Jamie Hall

There is, admittedly, one more or less valid reason to convert: it's easier to zone hot water than steam. Otherwise, there are hundreds of excellent reasons to not convert.

Don't do it.

ChrisJ

Jamie Hall said:

There is, admittedly, one more or less valid reason to convert: it's easier to zone hot water than steam. Otherwise, there are hundreds of excellent reasons to not convert.

Don't do it.

I'm going to ask......
Why is it easier to zone hot water than steam?

They're both hydronic, what's the big issue?

Long Beach Ed

We've done several conversions, where owners insisted the work be done.

What would you like to know about the experiences?

ethicalpaul

ChrisJ said:

Jamie Hall said:

There is, admittedly, one more or less valid reason to convert: it's easier to zone hot water than steam. Otherwise, there are hundreds of excellent reasons to not convert.

Don't do it.

I'm going to ask......
Why is it easier to zone hot water than steam?

They're both hydronic, what's the big issue?

You can have separate actual thermostats for the different zones that actually turn on/off the flow of hot water to those areas rather than messing with balancing steam flow and half measures such as TRVs.

retiredguy

My experience with conversions from steam to hot water was with large commercial buildings including schools and nursing homes. In these instances, and this is according the Building engineer or maintenance supervisor, is that there was a cost savings around 30%. The best explanation was that the savings came in the spring and fall when the system's water temp could be raised just a few degrees to heat the building instead of raising the boiler's temp to 212F and above to produce the steam, and then shutting off the boiler and loosing that sensible and latent heat of the water. Also, it was easier to zone the system for better temp control.

mattmia2

don't

The Steam Whisperer

retiredguy said:

My experience with conversions from steam to hot water was with large commercial buildings including schools and nursing homes. In these instances, and this is according the Building engineer or maintenance supervisor, is that there was a cost savings around 30%. The best explanation was that the savings came in the spring and fall when the system's water temp could be raised just a few degrees to heat the building instead of raising the boiler's temp to 212F and above to produce the steam, and then shutting off the boiler and loosing that sensible and latent heat of the water. Also, it was easier to zone the system for better temp control.

The big question that always come up is "What was the condition of the steam system before being converted?" Was it even in somewhat decent condition? The steam systems we have "converted" to modern steam systems easily produce 25 to 30% fuel savings, some around 50% when upgrading to outdoor reset modulating power burners. We haven't even touched condensing steam boiler technology yet in these systems, which would probably get another 5 to 7% improvement.

I am hoping in the next couple years to do a back to back comparison of steam to hot water using the same boiler, system and building in my own home.

randers2015

Thanks. Here is the situation: to get an erngy star boiler since there is no known energy star STEAM boiler. There is Hot Water boiler but not steam'

The current steam boiler cannot be repaired; i have to get a new one so, i want to get an energy start boiler and this is what I have been thinking about.

No this is a home and not commercial building.

mattmia2

You're going to spend way more trying to convert the system than you will ever save in fuel. get a properly sized steam boiler and fix any issues with the steam system.

EdTheHeaterMan

Since an energy star boiler will qualify for a one time rebate of $$$ and the higher efficiency will yield an annual savings of $$ for a total 20 year savings of $$$$.

Now compare this to the $$$$$ cost of the conversion. Will it be worth wile?

If you want an energy star appliance, you should just get a furnace with ductwork. That way, you can get central air conditioning at the same time.

Or you can get a price on a new steam boiler from someone in the FIND A CONTRACTOR link above.

Steamhead

randers2015 said:

Thanks. Here is the situation: to get an erngy star boiler since there is no known energy star STEAM boiler. There is Hot Water boiler but not steam'

The current steam boiler cannot be repaired; i have to get a new one so, i want to get an energy start boiler and this is what I have been thinking about.

No this is a home and not commercial building.

Not worth it. Keep the steam. You will never get any appreciable return on the huge investment it would take. Not to mention (because others already did) the potential pitfalls.

This subject comes up every so often. Here's one thread where someone tried to justify a conversion, which effort fell flat on its face:

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

The Burnham MegaSteam series was EnergyStar rated until recently.

pedmec

Do what i do. Build your manifold on your new wall as if your piping in mod/con and pipe it primary/secondary. Do a horseshoe manifold. Put the expansion tank, air separator, and feed valve on the new horseshoe manifold. install closely space tees. convert the steam boiler to hot water and tie the supply and return with circulator to the closely spaces tee's. now your when you want to buy the mod/con boiler you can just plug it into the existing set-up. no costly changes as you built everything on the wall.

It doesn't cost much to convert the remaining steam to hot water. just an aquastat, relay, relief valve, some gauge changes. And of course an electrician. you just got to be committed to the new boiler at some point because your setting it up for mod/con. More involved than just building the manifold right out of the cast iron boiler.

Big Ed_4

Post several photos of differant sides of the boiler

Jamie Hall

Left out a couple of points there. If the system is one pipe steam, you need all new piping and converting the radiators to have both a supply and a return. If it's two pipe, all you have to do is take all the traps out, make sure the valves are not steam throttling, make sure there are no orifices in them, revise the main and return piping to get a semblance of even distribution.

Then pressure test everything to 30 psi and replace everything that leaks at 20 times the steam pressure you've been running.

Then try to figure out how to pay for all that plus a new mod/con vs. just a new steam boiler which cost half as much to begin with as the mod/con did..

Right. The rebate is con. An ingenious one, true. Even legal. But it's a con.

Steamhead

In this thread-

https://forum.heatinghelp.com/discussion/190331/size-of-team-boiler-for-2300-sqft-house-3-floors-contractor-said-86-000-output-is-sufficient

the OP says this is one-pipe steam. That means running all new return lines- and the radiators themselves may not work with hot-water at all. Then there are the other pitfalls.

@Jamie Hall et al, you're right.

Long Beach Ed

If the socialists in your municipality will not permit anything but an EnergyStar boiler, buy a sticker on ebay and put it on a new steam boiler. The entire program is a money-sucking scam and you'll be the loser if you fall for it.

AdmiralYoda

If you are being forced to only buy an Energy Star boiler.... sounds like it would be cheaper and easier to just replace the entire heating system with forced hot water baseboard or similar.

If this a personal decision or a decision based on a rebate.... a new steam boiler will still be significantly cheaper and easier to install than the hot water alternative. By the time the efficiency savings make the payoff worth it...it will be time for a new boiler anyways.

randers2015

Thank you ALLL. All points are well taken. Appreciate the expertise and will stick with a new steam boiler system. May consider a split system in the future for the AC. We are using just window AC if we use that and lovely ceiling fans.

AdmiralYoda

@randers2015 Out of curiosity, have you had problems with your existing one-pipe steam system?

More often than not modifications and alterations to piping have been made over the years by less than competent "experts". Usually resulting in grossly oversized boilers and poor piping and venting. Perhaps post pictures of your near boiler piping for the pro's here to critique along with your main venting setup.
Do you know the EDR of your existing radiators and the steam capacity of your existing boiler?

A properly sized, piped and vented boiler can provide significant savings over an oversized poorly piped mess. Non-condensing atmospheric boilers for steam or hot water are about equally efficient. So you may still have the opportunity to be roughly as efficient as a hot water system but without spending the big $$$ to convert it and sticking with steam.

randers2015

The system is broken and done with.

randers2015

Jamie Hall

Well, it is an old boiler for sure. But sizing and putting a new one in to replace it would be no difficulty at all for a good steam man.

Jamie Hall

as I said in the other thread -- it should be no problem to put a new, properly sized boiler in there. If there aren't other problems it's an easy job.

mattmia2

That rollout likely isn't a problem that is the fault of the boiler. Whatever issue caused that will have to be addressed whatever is put in there.

ChrisJ

Those aren't pictures of the heating system, that's only the boiler.

The radiators and piping would cost a small fortune to have installed and are a big part of the system.

ethicalpaul

That's one broke-down, rusty-butt, beyond its expiration date, paid for itself 3x boiler, but that's not Steam's fault

ethicalpaul

Or woman

bburd

Insulating the steam pipes will go a long way toward improving fuel efficiency and the speed with which the system heats. There are many threads here on this subject. 1 inch fiberglass is the material of choice, not usually available at big box stores, but it can be ordered online. It’s a relatively easy DIY project.

Erin Holohan Haskell

I've merged all duplicate posts on this here. Thanks @ethicalpaul.

jumper

retiredguy said:

My experience with conversions from steam to hot water was with large commercial buildings including schools and nursing homes. In these instances, and this is according the Building engineer or maintenance supervisor, is that there was a cost savings around 30%. The best explanation was that the savings came in the spring and fall when the system's water temp could be raised just a few degrees to heat the building instead of raising the boiler's temp to 212F and above to produce the steam, and then shutting off the boiler and loosing that sensible and latent heat of the water. Also, it was easier to zone the system for better temp control.

Certainly easier and less expensive to convert to vacuum steam heat for spring & fall.

randers2015

Thank you everyone for your input!!!!. I will keep steam. I have found an excellent contractor that actually seem to be reasonable and had some similar points here about keeping stem, and not worth the conversion. Looking to have the work done in the next couple of months!

EBEBRATT-Ed

@randers2015

Just make sure before your contractor starts there are several key points that if missed ......well you will be sorry.

Make sure

He measures radiators this is the ONLY way to size a steam boiler
that he pipes the boiler in accordance with the install manual
Uses all black pipe for the steam,,,,copper allowed on the return lines below the boiler water line
that he skims and cleans the boiler after the install