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Low temperature unit hot water heaters

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sindu
sindu Member Posts: 1
in Radiant Heating
Some of the unit hot water heaters from Modine, Dayton, etc., specify 200F inlet water temperature. What are some unit heater that operate efficiently at 140F or lower inlet water temperature?

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  • Steamhead
    Steamhead Member Posts: 16,842
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    Those manufacturers should have lower-temperature ratings for their units- call them and see.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • hot_rod
    hot_rod Member Posts: 22,157
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    to operate at lower supply temperatures you need more fin surface area. The charts should tell you output at various supply or delta Ts. You may have to step up a few sizes to get the output you need at lower SWTs.

    Consider an air handler as another option, match a cased coil, filter rack, and an AC coil if needed ECM or true variable speed blowers are another option.

    I have mounted them horizontally in shops, they are much quieter also.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Fishingfool
    Fishingfool Member Posts: 4
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    Toyotomi has come out with a hydronic fan coil. It has it's own thermostat and a 3 speed blower. With a incoming water temp of 140 degrees F it will produce around 12,400 Btuh's . Take a look at it on their web site toyotomiusa.com product number HC-20 they work very well with Geo-thermal heat pumps.
  • Fishingfool
    Fishingfool Member Posts: 4
    edited July 2015
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    sorry no attachment.

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