base board heat with tankless water heater

Old 03-23-05, 11:46 AM
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Exclamation base board heat with tankless water heater

Is it possible to replace my old boiler that is need of repair with a tankless hot water heater? I have common baseboard heat.

I know I would have to move my circulator to the out line of the hot water heater and have my return go to the input line.

My concerns are flowrate...I have a Taco 007 Circulator which has a range of 0-20 gpm. Even the most industrial tankless system maxes out at 9 gpm. and the common resedential can be as low as 1.5 gpm

my other concern is that tankless systems say that the input water temp should be 50F. I would expect my returning tempreture to often by at least 70F to as high as 130F. does anyone know what this would do to the tankless water heater?

Has this sort of thing been done.. can it be done??? I work in the HVAC industry as an engineer but work with refrigeration...

thanks for you help
Old 03-23-05, 04:20 PM
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The problem with your boiler is only the domestic coil? Please elaborate on the needed repairs. I don't think you want a tankless water heater. Maybe an indirect.
Old 03-24-05, 09:02 AM
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Well its not that I need to replace the whole unit I jsut figured there could be a energy savings down the road if the water was only heated on demand and there was no need for a tank. I could eliminate the whole system. remove my oil tank and free up 25% of my basement along with having a more energy efficent system because it only heats when it needs to.
Old 03-24-05, 09:22 AM
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There are tankless units that provide more volume - up to 15 gpm. I think that for a heating system they generally require a small expansion tank. Do a search for tankless and then take a look at some of the web-sites. Some of them have rather extensive pdf's available that indicate what's needed and how they should be installed.

One link you might check is:

BTW, they have one unit that produces 9.6 gpm and you can install them in series if needed to get increased volumes.

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