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Using an electric tankless instead of a boiler.

Chris Burt
Chris Burt Member Posts: 19
in THE MAIN WALL
What is a good source for a heat exchanger? Also what do they usually cost? I need one capable of about a 30,000 btu heating load. Also how do you controll the second pump for the heat exchanger? My thermostat presently controlls the circulation pump directly.

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  • Chris Burt
    Chris Burt Member Posts: 19


    Has anyone here ever tried a small tankless electric water heater? I found found a few capable of my load I am just not sure about the adjuments. My Bosch Aquastar 240FX has a modulated flame to controll the output.
    What is a good source for a heat exchanger? Also what do they usually cost? I need one capable of about a 30,000 btu heating load. Also how do you controll the second pump for the heat exchanger? My thermostat presently controlls the circulation pump directly.
  • hr
    hr Member Posts: 6,106
    A sweet electric

    heater is this modulating Seisco. It will modulate from nothing to 28 amp current draw. As the unit approches setpoint temperature the output starts dropping back. Sort of a free reset control.

    Gas or LP are always my first choice, but in some areas it is just not an option.

    Try john@azuresupply.com he has a lot of experience with this unit.

    hot rod

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  • Mark Eatherton1
    Mark Eatherton1 Member Posts: 2,542
    Thats a thang of beauty...

    if'n I ever did see one. Do you pass out color matched brochures in the mechanical room? WHEW, it's purdy.

    HR, is that a fully modulating board or is it stepped in fixed KW increments. Looks like a lot of electronics to me!!

    ME

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  • hr
    hr Member Posts: 6,106
    Modulates all over

    the place. Basically this unit is two 6 KW water heater elements in a small plastic tank and a large circuit board. Not a very expensive unit to purchace either!

    I have an interior designer meet with the clients. The designer decides which colors will most likely encourage the owners to spent money on radiant heat:)

    I leave behind a thank you along with warranty info, photos of the tube layout, wiring info, and a small essay on the control system.

    The expansion tank is remote mounted with PAP.

    hot rod

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  • Brian (Tankless) Wood
    Brian (Tankless) Wood Member Posts: 222
    A teeny correction

    Hi HotRod, your fieldpiece is reading 28.5 amps on startup. That must be a Seisco RA-14, with two 7,000 watt elements. Almost 48,000btu's in/out at 99.7% eff, from an infinitely modulating heat source that only weighs about 14 lbs!

    This the best thought-out electric tankless heater on the market: off-the-shelf elements, water cooled element control triacs, no flow switch, it's done by SENSING flow through temp differences. Element relays never make or break under power. Water level detect/shutdown, hi-limit, and three thermistors which monitor flow, and control temp of the unit, via temp's collected at different points in the unit. 3/4" pipe fittings, board-mounted thermostat.

    These are pretty smart water heaters, and the only t/static kind I will sell or install down here in Swampland (130 so far). It's a nice coincidence that I know the guys at Microtherm, just down the road in Houston, a couple of hours away.

    The attached photo is a 28 kw unit that I installed in my lawyer's home library. It's directly beneath the 200amp panel, and directly behind his master bathroom. I removed the storage tank heater and enlarged the size of the laundry room.

    * A T&P valve is not needed on a water heater containing less than one gallon.

    If anyone needs more info, let me know.

    Regards to all, Brian.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    was

    that the RA-11, HR? What a cool set-up.

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  • hr
    hr Member Posts: 6,106
    A 14 I believe, Bob

    but this is one case where a bit of an over size will not hurt you, as the unit can modulate down. It would cost a bit more wire and circuit size however.

    This unit was wired with two 30 amp 240 volt circuits. A little easer to run than a 60 amp circuit, wire and condiut size wise.

    hot rod

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