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Class Information
Number: 392/454
Name: Electric resistance heating devices > Heating devices (class 219 subclass 200) > Tank or container type liquid heater > Line connected tank > With immersion heating element > Plural heating zones
Description: Subject matter wherein the heating device is located in at least two or more separate areas of the tank to be heated.

Patents under this class:
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Patent Number Title Of Patent Date Issued
8498527 Water heating control and storage system Jul. 30, 2013
8385729 Heat pump water heater and associated control system Feb. 26, 2013
8355625 System for and a method of heating water Jan. 15, 2013
8008603 Boiler protection apparatus and method Aug. 30, 2011
7989739 Electric heater assembly Aug. 2, 2011
7970264 Water dispenser with Sabbath function Jun. 28, 2011
7693402 Thermal storage unit and methods for using the same to heat a fluid Apr. 6, 2010
7644686 Water heating distribution system Jan. 12, 2010
7620302 High efficiency, peak power reducing, domestic hot water heater Nov. 17, 2009
7570877 Electric water heater that keeps the hot water at a preset temperature constantly Aug. 4, 2009
7560672 Heated pump with boiling protection Jul. 14, 2009
7373080 Water heater and method of operating the same May. 13, 2008
7103272 Water heater and method of operating the same Sep. 5, 2006
7027724 Water heater and method of operating the same Apr. 11, 2006
6989514 System and method for controlling temperature control elements that are used to alter liquid temperature Jan. 24, 2006
6957014 Liquid heater Oct. 18, 2005
6785466 Electric water heater having balanced wattage density water heating Aug. 31, 2004
6465764 Water heater and control system therefor Oct. 15, 2002
6370328 Water heating tank with thermosiphonic circulation for improved heat recovery rate Apr. 9, 2002
6363216 Water heater having dual side-by-side heating elements Mar. 26, 2002
6350967 Energy saving water heater control Feb. 26, 2002
6349169 Attachment structure for vessel fitting Feb. 19, 2002
6308009 Electric water heater with electronic control Oct. 23, 2001
6271505 Field conversion electric water heater Aug. 7, 2001
6265699 Water heater with electronic control Jul. 24, 2001
6137955 Electric water heater with improved heating element Oct. 24, 2000
6002114 Control device for an electric water heater Dec. 14, 1999
5968393 Hot water controller Oct. 19, 1999
5949960 Electric water heater with dry fire protection system incorporated therein Sep. 7, 1999
5898818 Water feed system at constant temperature keeping the hot water from mixing with the cold water fed during use of the hot water in a single tank Apr. 27, 1999
5808277 Programmable thermostat to reduce bacterial proliferation to prevent legionellosis Sep. 15, 1998
5712951 Electric water heater with primary and secondary pre-heatng chambers Jan. 27, 1998
5692096 Protection and control of continuous boiling water units Nov. 25, 1997
5495551 Fast recovery circuit for heat pump water heater Feb. 27, 1996
5433379 Dual tank water heating system Jul. 18, 1995
5404421 Fuel heating element mounting plug housing a thermostat Apr. 4, 1995
5255338 Heat pump water heater control circuit Oct. 19, 1993
5187772 Electric water heater with radially extending overlapped horizontal heating element arranged in vertically spaced aligned sets Feb. 16, 1993
5168546 Device for heating the bacterial proliferation zone of a water heater to prevent legionellosis Dec. 1, 1992
5115491 Tempering system for storage tank water heaters utilizing inlet and outlet heat exchanger May. 19, 1992
5103801 Automatic cooking vessel Apr. 14, 1992
5078123 Electric water warming system Jan. 7, 1992
4948948 Water heater with multiple heating elements having different power Aug. 14, 1990
4935603 Hot water supply system Jun. 19, 1990
4777347 Electric water heating tank with thermosiphonic circulation for improved heat recovery rate Oct. 11, 1988
4737615 Energy saving control circuit for hot water heater Apr. 12, 1988
4551612 Wall-contained electric water heating tank Nov. 5, 1985
4511790 Multiple load control apparatus having load equalization Apr. 16, 1985
4419567 Heating element for electric water heater Dec. 6, 1983
4416222 Hot water heater circuitry Nov. 22, 1983

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