Is it worth it to convert from steam to hot water?

I am planning or at least considering installing another EFM stoker (already have it). The unit currently in place is a 520 highboy with a badly rusted base, (I drilled and tapped 3 inch angle iron to each corner some time back), weak domestic hot water coil (never replaced) in over 50 years. I have a much newer unit that was originally set up for hot water sitting in my cellar. The unit is fired year round.

So I guess I have a number of choices, continue using the exisitng unit.
Refurbish the existing unit, new base, new domestic coil etc.
Install other unit as a steam system
install other unit as a hot water system.

I do plan to continue to live there for a long time, I hope, so while money is an issue it is not the primary deciding factor.

On other thing I would like to change is that I have 3 upstairs bedrooms that do not have heat, one that does, ($ was a deciding factor when my Father installed the system). Hot water would be more efficient and perhaps more easily zoned, but with good steam vents that isn't too much of an issue.

Advice and plusses or minuses would be appreciated. Also, how much more efficient is HW than steam? Thanks in advance, Jim

I've got an old house with a steam system. The steam throws a lot of heat when you need it, but the rest of the time the hot/cold swings are kind of annoying. After looking at different possible multiple boiler scenarios, this year I'm going to try to set up a couple of zones using water from the steam boiler to feed hw/air heat exchangers (maybe radiant heat in one room). I hope to get steadier heat at lower boiler temps with the hw, but still be able to crank up the steam when it's real cold. You might want to consider that kind of approach (e.g., w/hw baseboard?) for your unheated rooms.

I'm not an expert, but I think there is a measurable efficiency difference between hw and steam. Steam operates at a higher temperature differential (greater heat loss), and when it shuts down, the heat from 212 deg. water goes up the chimney.

Good luck.

Mike

I get the impression you currently have a steam system. I'm no steam expert.

If you have a two-pipe system, you might be able to clean everything up from the sludge and use hot water. But you have two things against you. Steam runs on 1 to 1 1/2# of pressure and the same radiators that used steam probably won't have the same output as hot water. At 13# of pressure, you might have leaks.

Maybe the coil only needs to be acid cleaned, or maybe it's covered with a ton of sludge, or maybe the water level isn't high enough to cover it completely.

Also have steam heat, 1 pipe system, and wouldn't give it up in this old 1925 house. Hot water baseboard would be a pain to install, maybe not the first floor but getting the pipes up to the second story. I don't see how you say the " heat goes up the chimney when the steam is off"? It does take more energy to heat water to boiling, but a must read is a few of the books written by Dan Houlihan on steam heat. They no doubt helped me a lot setting up the radiator vents sizing and what pressure to run and set things at. Plus is less moving parts and that is always a plus. I will easily trade burning a few more pounds of coal over circulator pumps, water piped under pressure, bleeding the system, expansion tanks, zone valves, higher electricity usage. I have heat when we lose power during a storm. Manual feed, manual ashing. Yes you can boil water at less than 212, some steam systems are set up with a vacuum system(using your chimney draft). Are all the fittings for steam on the new boiler? If not, i would rebuild the old one now while its summer time.

If you have a one pipe system, you would need to do a lot of work to convert to HW. Even a two pipe system may require additional radiation, controls, etc, all of which cost money. I would put the steam controls on the hot water boiler and swap them. IIRC, all EFM boilers are rated for steam. If it is H stamped, you are all set.

you could leave the 1st floor on steam and then take off from the water leg of the boiler and run forced hot water to basebord or rads or convectors as a seperate zone on the 2nd floor

jimg wrote:I am planning or at least considering installing another EFM stoker (already have it). The unit currently in place is a 520 highboy with a badly rusted base, (I drilled and tapped 3 inch angle iron to each corner some time back), weak domestic hot water coil (never replaced) in over 50 years. I have a much newer unit that was originally set up for hot water sitting in my cellar. The unit is fired year round.

So I guess I have a number of choices, continue using the exisitng unit.
Refurbish the existing unit, new base, new domestic coil etc.
Install other unit as a steam system
install other unit as a hot water system.

I do plan to continue to live there for a long time, I hope, so while money is an issue it is not the primary deciding factor.

On other thing I would like to change is that I have 3 upstairs bedrooms that do not have heat, one that does, ($ was a deciding factor when my Father installed the system). Hot water would be more efficient and perhaps more easily zoned, but with good steam vents that isn't too much of an issue.

Advice and plusses or minuses would be appreciated. Also, how much more efficient is HW than steam? Thanks in advance, Jim

Refurb the 520 High boy it has more water capacity 74 gal Vs 40 to 41 Gal on a Standard 520 PM Me if you want a replacment high boy base . When you say a weak water coil do you mean it is leaking around the rubber gasket if so replace the gasket with a new one . If the steel is rusted out around the coil area then you need a repair Plate welded
on the back cut the bad area out and weld the new plate on flush . Make sure the welder has a R stamp certification.
find some cast iron radiators to install in the rooms with out heat radiators hold the heat better then baseboard does
a little more work with rads as far a weight goes .

coaledsweat wrote:If you have a one pipe system, you would need to do a lot of work to convert to HW. Even a two pipe system may require additional radiation, controls, etc, all of which cost money. I would put the steam controls on the hot water boiler and swap them. IIRC, all EFM boilers are rated for steam. If it is H stamped, you are all set.

There where only a few early efm 350's that where not H stamped The round top boilers. All 520 700 900 1300 Had H stamps . Because they where all made for Commercial & Residential Use . The early Round top boiler 350 where not made for Commercial use only Residential use that is why they do not have the H stamps on them But the Square top 350
boilers do have the H stamp on them at least the 20 or more 350's Sq tops that I seen did . None of the 8 or so round top 350 that I have seen had the H stamp on them . And every 520 high boy or Standard 520 which is well over 50 had the H stamp on them . The 7 or so 700 that I have seen all had the H stamped aswell as the 4 1300 I have seen only ever seen
2 900 both had the H stamp

Thank you for all the ideas and information. This is a one pipe steam system. The boiler is not leaking around the domestic coil, it probably could use a good acid bath. I am familiar with keeping the water level within a certain range within the boiler so I don't think that is a problem. I think a refurb of the existing unit and additional steam radiators might be the best idea.

I wasn't aware that you could run both steam and HW from the same unit, are there issues surrounding that? Since I won't be doing this myself, I believe my next step is to get someone in to take a look at what will be required. I live in lower Northumberland county. PM'd recommendations would be appreciated. Thank you again, Jim

You might find a couple of books interesting and helpful to control your system - conversion to hot water may/ should not be necessary if the system is performing correctly

http://www.heatinghelp.com/shopcart/pro ... tegory=2-3

http://www.heatinghelp.com/shopcart/pro ... gory=2-109

But if you want 180 degree water, while making steam - you throttle the boiler bypass and blend return water with boiler water, that will ensure the water in the zone will never flash to steam when the circulator shuts off. Fill that zone separately from the boiler using two boiler drains with gate valves. Control the circulator on that zone with a room thermostat, a high limit aquastat and a DPST switching relay

Quote: When it comes to Steam Heating, if it makes sense, don't do it!