# steam radiators to fhw



## bct p&h (Jan 19, 2013)

This is actually in my own house. House was built in 1890 and has 10 very decorative steam radiators along with some cast iron steam baseboard to heat the house. It's all single pipe so I know I'll have to repipe everything but I'd like to reuse the radiators. I know the cast iron baseboard will work with forced hot water but because the radiators are only joined at the bottom I'm having my doubts that they will work with fhw. I've done conversions in other peoples houses but they already had fhw radiators, connected top and bottom. I'm worried that if I try to pipe mine in I'll end up with constant air purging because I won't be able to purge out the tops of the radiators and they won't heat as well because the hot water will only be running through the very bottom. Am I over thinking this or should I scrap this idea along with my 120+ year old radiators?


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## rjbphd (Feb 5, 2010)

bct p&h said:


> This is actually in my own house. House was built in 1890 and has 10 very decorative steam radiators along with some cast iron steam baseboard to heat the house. It's all single pipe so I know I'll have to repipe everything but I'd like to reuse the radiators. I know the cast iron baseboard will work with forced hot water but because the radiators are only joined at the bottom I'm having my doubts that they will work with fhw. I've done conversions in other peoples houses but they already had fhw radiators, connected top and bottom. I'm worried that if I try to pipe mine in I'll end up with constant air purging because I won't be able to purge out the tops of the radiators and they won't heat as well because the hot water will only be running through the very bottom. Am I over thinking this or should I scrap this idea along with my 120+ year old radiators?


 Are the radiators connected at top? And why you have to repipe?


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## bct p&h (Jan 19, 2013)

rjbphd said:


> Are the radiators connected at top? And why you have to repipe?


Only at the bottom so supply and return would be straight across from each other. Only bleeder on the radiator would be on the last section. I would have to repipe the system because it's single pipe steam, doesn't work too well with forced hot water.


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## rjbphd (Feb 5, 2010)

bct p&h said:


> Only at the bottom so supply and return would be straight across from each other. Only bleeder on the radiator would be on the last section. I would have to repipe the system because it's single pipe steam, doesn't work too well with forced hot water.


Why u want to repipe into forced hot water? What's wrong with thbe steam you have now?


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## bct p&h (Jan 19, 2013)

rjbphd said:


> Why u want to repipe into forced hot water? What's wrong with thbe steam you have now?


1-$700+ a month gas bill in the winter. Can't get the efficiency out of steam that you can with a hi-eff forced hot water boiler.

2- One thermostat controlls a 2,500 sq foot 2 story house. My entire steam main is welded so cutting in steam valves and repiping the second floor for steam isn't exactly something I want to do. 

3- Current boiler is 20+ years old with the fill piped into the block Instead of the return like it should have been. It's only a matter of time before it cracks and I'd rather swap it over before that happens in the middle of the winter.

4- Because it's my house and I do what I want:laughing:


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## rjbphd (Feb 5, 2010)

bct p&h said:


> 1-$700+ a month gas bill in the winter. Can't get the efficiency out of steam that you can with a hi-eff forced hot water boiler.
> 
> 2- One thermostat controlls a 2,500 sq foot 2 story house. My entire steam main is welded so cutting in steam valves and repiping the second floor for steam isn't exactly something I want to do.
> 
> ...


Betcha that boiler was piped wrong for that high fuel cost, yes u can increase the efficiency on steam system, u just gotta know what ya doing... got any pictures?


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## bct p&h (Jan 19, 2013)

rjbphd said:


> Betcha that boiler was piped wrong for that high fuel cost, yes u can increase the efficiency on steam system, u just gotta know what ya doing... got any pictures?


No pics and not sure how to post one from my phone.
I am no expert when it comes to steam but I know more than most. They didn't do a horrible job piping the boiler aside from feeding into the block. At least they didn't pipe it like most I've seen that bang themselves to death.
No matter how it's piped the best efficiency that boiler will ever see is low 80s. I don't hate steam but I'd like zone control and higher efficiency. I also wouldn't mind using the chimney that the boiler is currently dumping into for a fireplace in my master bedroom


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## Gettinit (May 9, 2012)

I would slap a hw Buderus in there if it were a two pipe system. Auto vents or the old school key operated valves can be installed in the radiators to purge the air out. Worst case you can tap and thread the radiator for the vent. You could do better on the efficiency of the burner unless it is a ribbon/tube type. It does sound like something is piped wrong or the auto feed needs to be replaced. Some just put too much water into the boiler. What does the sight gauge look like? Pressures? Is the house balanced?


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## theplumbinator (Sep 6, 2012)

Worst case you could replace radiators and get fancy covers for them to hide the plain generic look of modern rads. 

Or remove and sell them people pay good money for the decorative older steam rads.
Your going to have a hard time getting the end plug and old spuds out of the old rads anyway. Add drilling and tapping a bleed port to cast iron and I would say its not worth the hassle. 

There are ways to zone steam systems these days with thermostatic rad valves. Check out the Dan Holohan book " greening up your steam" lots of tricks to increase the overall system efficiency of even an old steam boiler. Flame efficiency doesn't mean crap really, its something boiler manufacturers believe will sell boilers. If there are piping issues and radiation location issues a 99% boiler isn't going to give you 99% overall system efficiency, that's what you should really care about anyway (Not that any manufacturer claims 99% efficiency anyway especially on steam). Size to me is the most important part of efficiency, and the most overlooked and mistaken part of boiler installs. Sometimes we are limited with changing steam boilers too much due to existing system Pipeing, but if you zone it, boiler size adjustments can be made.

No reason you couldn't keep your steam system with some easy modifications to modernize it to today's fuel prices. I have customers with steam that get better heat and fuel economy than other customers that have poorly planned hot water systems.


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## rjbphd (Feb 5, 2010)

theplumbinator said:


> Worst case you could replace radiators and get fancy covers for them to hide the plain generic look of modern rads.
> 
> Or remove and sell them people pay good money for the decorative older steam rads.
> Your going to have a hard time getting the end plug and old spuds out of the old rads anyway. Add drilling and tapping a bleed port to cast iron and I would say its not worth the hassle.
> ...


How come I'm only allowed one thank???


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## rjbphd (Feb 5, 2010)

theplumbinator said:


> Worst case you could replace radiators and get fancy covers for them to hide the plain generic look of modern rads.
> 
> Or remove and sell them people pay good money for the decorative older steam rads.
> Your going to have a hard time getting the end plug and old spuds out of the old rads anyway. Add drilling and tapping a bleed port to cast iron and I would say its not worth the hassle.
> ...


I have improved the steam heating systems after redoing the hackery's doings. Believe it or not, most plumbers don't have a freakin clue about steam and they are called for jobs as public percieved that pipes are just pipes.


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## theplumbinator (Sep 6, 2012)

rjbphd said:


> How come I'm only allowed one thank???


From one hydronic guy to another one thank is all I need lol.


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## theplumbinator (Sep 6, 2012)

Not many guys can appreciate the multiple HOURS I have spent on educating myself on how steam systems work. Only 5% of homes in America use hydronic heat and that includes both steam and hot water so we are a minority among most of the rest of the countries plumbers and mechanical contractors. Any chance I get to broaden my knowledge I take the opportunity. Especially steam there aren't many outlets you can get first hand knowledge from these days. Most of the guys that installed steam are dead.


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## Tommy plumber (Feb 19, 2010)

theplumbinator said:


> Not many guys can appreciate the multiple HOURS I have spent on educating myself on how steam systems work. Only 5% of homes in America use hydronic heat and that includes both steam and hot water so we are a minority among most of the rest of the countries plumbers and mechanical contractors. Any chance I get to broaden my knowledge I take the opportunity. Especially steam there aren't many outlets you can get first hand knowledge from these days. Most of the guys that installed steam are dead.


 







I purchased these to broaden my knowledge about steam....


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## rjbphd (Feb 5, 2010)

Tommy plumber said:


> I purchased these to broaden my knowledge about steam....


Nothing beats the TLAOSH book!!


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## theplumbinator (Sep 6, 2012)

Audel= great resource, I have volume1. Gotta get 2&3.


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## theplumbinator (Sep 6, 2012)

One of my favorites is anything by Dan "the man" Holohan.


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## rjbphd (Feb 5, 2010)

theplumbinator said:


> One of my favorites is anything by Dan "the man" Holohan.


Got them all! And more on the way!


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## Plumbworker (Oct 23, 2008)

Forced hot water will work just fine with cast iron radiators with circulation taps at the bottom.. i have this system in my own home.. the entire rad is totally hot within minutes heats the house very nicely. The system was existing it's a single zone system for 1800sqft of home. It only has one thermostat in the foyer.. since then i've added TRV's to the supply of each rad and its been working quite well.
This summer I'm going to be replacing the old conventional cast iron boiler with a mod-con i'm removing the trv's and going to zone each room with valves and install a delta t circulator to bring new technology and efficiency to the system... i'm also considering installing a hydraulic and dirt separator.


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## Rufcar (Oct 26, 2013)

*Steam again on an old thread*

I saw this today and thought id add a bit. I live in an 112 yr old brick home with one pipe steam. 30 yrs ago I removed the oil and installed a van wert 600,000 btu steam boiler. I moved all the rads to under windows from inside walls and now heat all 6,000 sf with 1 thermostat and all rads heat equally and I use about 18 tons of hard coal at $200 a ton delivered! Plus its making my hot water 24/7. I figure with $4.00 a gal fuel oil and 160 gal per ton conversion and I used 4500 gal a yr previously my payback was very short!
Your steam system must have a problem your not seeing. I read where you were just getting Holahans book? Did that help?
You can't use steam only rads for hot water to my knowledge! Youll need hot water only type with a tube in top and bottom. Also it can be done but its not recomended to mix base board with vertical radiators. 
Take off piping size and pitch mean alot. 
I know this is an older post and that your system migh have already been changed but was hoping this might help if your not finished yet.


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## rjbphd (Feb 5, 2010)

I've done many from steam to hot water converison.. there are many risks involved. Since becoming more knowledgable in steam system, I maintained, bring it back to orginial state if the system haven't been too basterdized by plumbers or forced air people.


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