2nd Zone (circulating HW) off Steam Boiler via Tankless Option

Seth_3

How effective is using a tankless hotwater system on a steam boiler as a feed for circulating hot water to form a second heating zone? I've got a few rooms without radiators on the third floor of my home that need supplmental heat and wondered how effective/efficient it would be? The other option would be to install a second package gas heating system in the attic - but that seems like it might be overkill. Thoughts?

Tom_40

I have used a tankless coil in a steam boiler numerous times to produce multiple zones of forced hot water heat. Make sure to use a high limit in the forced hot water zone, usually set for 180 F, to prevent the boiler from making steam when steam is not wanted.

WPH2205

Using a tankless coil off a steam boiler for a hot water zone works great. Be sure to pipe it just as you would a hot water boiler, only you will be using the coil as your "boiler". Start with the upper tapping for the supply. Install an air separator, bladder-type expansion tank, circulator(pumping away from tank) and purge valve on the return. It will work beautifully.

Steve Garson

Wouldn't it be more efficient to run a hot water loop right off the boiler water, like Dan describes?

Unknown

Both ways work well

We've installed many zones of baseboard heat using both methods . There is a limit to how high above the boiler you can run a loop if it's connected directly to the steam boiler water . Other than that , if you choose the right type of circulator and pipe it correct , I believe this method will work as well as setting up a separate zone of heat on a tankless coil .

Ken_8

I beg to disagree...

Depsite Ron Jr's wizardly ways I suggest the tankless coil affords the distinctive advantage of being a truly closed system. Anytime you run steam rust, scale and junk through any pump you risk blowing the seal; or in the case of a wet rotor pump, jamming the cartridge with junk and seizing the rotor.

The other limiting factor is a requirement to have adequate pump head to lift the water with the open system approach. Using the sealed D/H/W coil makes the static fill pressure prevent the circulator from having to "pump," and allows it to simply circulate.

I have never seen an open steam/water zone circulator last more than 2-3 years - even with a wye strainer! And guess what happens to the wye strainer after the first year or so. Plug city.

Now if you have a boiler with no coil opening, take everything I just said and chuck it.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

I would agree with you Ken

Not only can that ooze screw up the circulator , I wonder what it does to the output of baseboard ? But time and again we are replacing steam boilers with wet rotor pumps that are 10 years old or more and still running . We just changed a system out last week . I didn't get the date code on the Taco 007 , but it was the older style body , and I'm guessing it was at least late 80s . You can just make it out low and close to the boiler .

Jim Burke comfort zone

try this

use a phase 3 indirect off the steam return as shown in dans book don't forget the blending valve so as not to have it flash to steam and then pipe domestic side of tank as yo would pipe a boiler .

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"