FIELD CONVERSION ELECTRIC WATER HEATER

Abstract

An electric water heater has upper and lower electric resistance type heating elements respectively controlled by a single pole, double throw upper thermostat and a single pole, single throw lower thermostat. The upper and lower thermostats are operatively interconnected by a wiring harness having outer conductor end portions that are connected to a terminal block portion of an external junction box to provide the water heater with a variety of heating element operating modes without having to replace either of the thermostats, vary the wiring harness interconnections therebetween, or vary the connection between the outer conductor end portions and the terminal block. The water heater may thus be advantageously manufactured in a single variant that may be easily and quickly modified in the field to selectively alter the heating element control mode of the water heater.

Claims

1-20. (canceled)

21. A liquid heating apparatus comprising: a tank configured to hold a liquid; a first electric heating element configured to provide heat to the liquid; a first thermostat configured to control the first electric heating element; a second electric heating element configured to provide heat to the liquid; a second thermostat configured to control the second electric heating element; a terminal block having (i) line side terminals configured to interchangeably connect to electrical power supply conductors and (ii) heating side terminals; and wiring connected to the first and second thermostats and the heating side terminals in a manner such that, without replacing either of the first and second thermostats or altering the wiring to either of the first and second thermostats or the heating side terminals, a selective portion of the electrical power supply conductors is connected to the line side terminals to provide the liquid heating apparatus with a plurality of heating element control modes, the plurality of heating element control modes including a single-phase control mode and a three-phase control mode.

22. The liquid heating apparatus of claim 21, wherein the plurality of heating element control modes includes simultaneous operation of the first and second electric heating elements and non-simultaneous operation of the first and second electric heating elements.

23. The liquid heating apparatus of claim 21, wherein the plurality of heating element control modes includes simultaneous energization of the first and second electric heating elements and sequential energization of the first and second electric heating elements.

24. The liquid heating apparatus of claim 21, wherein the plurality of heating element control modes comprises at least two of: a dual independent branch circuit element control mode; a single-phase simultaneous dual element control mode; a single-phase non-simultaneous dual element control mode; a single-phase non-simultaneous dual element control mode with four wire outlet operation; a single-phase non-simultaneous dual element control mode with three wire outlet operation; a three-phase simultaneous dual element control mode; or a three-phase non-simultaneous dual element control mode.

25. The liquid heating apparatus of claim 21, wherein the first and second electric heating elements are located at different heights within the tank.

26. The liquid heating apparatus of claim 21, wherein the first and second electric heating elements are resistive heating elements.

27. The liquid heating apparatus of claim 21, wherein: the first thermostat is a single pole double throw thermostat, and the second thermostat is a single pole single throw thermostat.

28. The liquid heating apparatus of claim 21 further comprising one or more jumpers interchangeably connectable to the line side terminals or the heating side terminals to enable each of the plurality of heating element control modes.

29. The liquid heating apparatus of claim 28, wherein each of the one or more jumpers is of a uniform size.

30. The liquid heating apparatus of claim 21, wherein the terminal block is incorporated in a junction box removably securable to the liquid heating apparatus.

31. A liquid heating apparatus comprising: a tank configured to hold a liquid; a first electric heating element configured to provide heat to the liquid; a first thermostat configured to control the first electric heating element; a second electric heating element configured to provide heat to the liquid; a second thermostat configured to control the second electric heating element; a terminal block having (i) line side terminals configured to interchangeably connect to electrical power supply conductors and (ii) heating side terminals; and wiring connected to the first and second thermostats and the heating side terminals in a manner such that, without replacing either of the first and second thermostats or altering the wiring to either of the first and second thermostats or the heating side terminals, a selective portion of the electrical power supply conductors is connected to the line side terminals to provide the liquid heating apparatus with a plurality of heating element control modes, the plurality of heating element control modes including a simultaneous dual element control mode and a non-simultaneous dual element control mode.

32. The liquid heating apparatus of claim 31, wherein the plurality of heating element control modes includes simultaneous energization of the first and second electric heating elements and sequential energization of the first and second electric heating elements.

33. The liquid heating apparatus of claim 31, wherein the plurality of heating element control modes includes a single-phase control mode and a three-phase control mode.

34. The liquid heating apparatus of claim 31, wherein the plurality of heating element control modes comprises at least two of: a dual independent branch circuit element control mode; a single-phase simultaneous dual element control mode; a single-phase non-simultaneous dual element control mode; a single-phase non-simultaneous dual element control mode with four wire outlet operation; a single-phase non-simultaneous dual element control mode with three wire outlet operation; a three-phase simultaneous dual element control mode; or a three-phase non-simultaneous dual element control mode.

35. The liquid heating apparatus of claim 31, wherein the first and second electric heating elements are located at different heights within the tank.

36. The liquid heating apparatus of claim 31, wherein the first and second electric heating elements are resistive heating elements.

37. The liquid heating apparatus of claim 31, wherein: the first thermostat is a single pole double throw thermostat, and the second thermostat is a single pole single throw thermostat.

38. The liquid heating apparatus of claim 31 further comprising one or more jumpers interchangeably connectable to the line side terminals or the heating side terminals to enable each of the plurality of heating element control modes.

39. The liquid heating apparatus of claim 38, wherein each of the one or more jumpers is of a uniform size.

40. The liquid heating apparatus of claim 31, wherein the terminal block is incorporated in a junction box removably securable to the liquid heating apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a highly schematic cross-sectional view through a field conversion dual element electric water heater embodying principles of the present invention;

[0018] FIG. 2 is a schematic wiring diagram of a thermostat/heating element portion of the water heater;

[0019] FIG. 3 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater;

[0020] FIG. 4 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater for a dual independent branch circuit installation;

[0021] FIG. 5 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater for a single phase simultaneous dual element control mode;

[0022] FIG. 6 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater for a single phase non-simultaneous dual element control mode;

[0023] FIG. 7 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater for a single phase non-simultaneous dual element control mode with four wire outlet operation;

[0024] FIG. 8 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater for a single phase non-simultaneous dual element control mode with three wire outlet operation;

[0025] FIG. 9 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater for a three phase simultaneous dual element control mode; and

[0026] FIG. 10 is a schematic diagram of a junction box/terminal block structure operatively associated with the heating element control thermostats of the water heater for a three phase non-simultaneous dual element control mode.

DETAILED DESCRIPTION

[0027] Schematically illustrated in FIG. 1 is a dual element electric water heater 10 embodying principles of the present invention. Water heater 10 includes a vertically oriented cylindrical metal water storage tank 12 which has, at its top end, suitable water inlet and outlet piping connections 14 and 16. Vertically spaced apart elongated upper and lower electric resistance type water heating elements 18 and 20 longitudinally extend horizontally into the interior of the tank 12 from a vertical sidewall portion thereof. The tank 12 is surrounded by an insulation jacket structure 22 including an outer metal skin portion 24 and a foamed-in insulation material 26 interposed between the metal skin portion 24 and the tank 12.

[0028] Extending along a vertical side portion 12a of the tank through which the upper and lower heating elements 18 and 20 inwardly extend is an insulating structure 28, such as a bag or another type of construction, which is designed to incorporate the insulating material 26 and provides a vertically spaced pair of peripherally sealed access openings 30 and 32 extending therethrough and respectively positioned somewhat above the outer ends of the upper and lower heating elements 18 and 20. Openings 30, 32 are respectively aligned with sidewall access openings formed in the jacket metal skin portion 24 and covered by removable access plates 34 and 36. Upper and lower electric thermostats 38 and 40 are respectively received in the access openings 30 and 32 and may be accessed by removing the plates 34 and 36

[0029] The upper and lower thermostats 38 and 40 are respectively and controllingly coupled to the upper and lower heating elements 18 and 20 and are electrically interconnected to one another by a subsequently described wiring harness 42 which is disposed between the insulation 28 and a vertical sidewall portion of the tank 12. During shipment of the water heater 10, upper end portions of various individual conductors which make up the harness 42 are placed in a top end well area 44 in the water heater 10 for subsequent operative connection to a terminal block portion 46 of a junction box 48. The term “conductor” as used in this patent application refers to electrical conductors and can include, as non-limiting examples, a wire, a lead, a cable, or a busbar. Representatively, the junction box 48 is shipped loose with the water heater and is subsequently attached to a top end portion thereof as schematically depicted in FIG. 1. In other embodiments, the well area 44 and the junction box 48 may also be attached or placed in an enclosure at the front of the water heater.

[0030] Turning now to FIG. 2, in the illustrated preferred embodiment of the dual element electric water heater 10, the upper thermostat 38 is of a single pole double throw configuration and has an ECO (energy cut-off) high limit control portion 38a operatively associated with a switch portion 38b, and the lower thermostat 40 is of a single pole single throw configuration and has an ECO high limit control portion 40a operatively associated with a switch portion 40b.

[0031] The upper thermostat ECO portion 38a has power supply terminals 50, 52, 54, and 56, and the upper thermostat switch portion 38b has a switch power terminal 58 and switch contacts 60 and 62. The lower thermostat ECO portion 40a has power supply terminals 64, 66, 68, and 70, and the lower thermostat switch portion 40b has a switch power terminal 72 and a switch contact 74.

[0032] Wiring harness 42 includes a conductor 76 interconnected between the power supply terminal 54 and the switch power terminal 58; a conductor 78 interconnected between the switch contact 60 and the upper heating element 18; a conductor 80 interconnected between the power supply terminal 56 and the upper heating element 18; a conductor 82 interconnected between the power supply terminal 68 and the switch power terminal 72; a conductor 84 interconnected between the switch contact 74 and the lower heating element 20; and a conductor 86 interconnected between the power supply terminal 70 and the lower heating element 20.

[0033] The wiring harness 42 also includes five water heater power connection conductors WH.sub.i, WH.sub.2, WH.sub.3, WH.sub.4, and WH.sub.5 which are connected to the terminal block portion 46 of the junction box 48. As subsequently described, selectively variable connections or using jumpers or other connectors in the terminal block 46 provide the upper and lower heating elements with a variety of control modes without the necessity of removing and replacing either of the thermostats 38 and 40, altering any of the wiring that interconnects the thermostats 38 and 40, or altering the wiring that interconnects the five water heater power connection conductors WHi, WH.sub.2, WH.sub.3, WH.sub.4, and WH.sub.5 to the terminal block 46. The power connection conductors WHi, WH.sub.2, WH.sub.3, WH.sub.4, and WH.sub.5 extend upwardly from the thermostats 38 and 40 behind the insulation structure 28 (see FIG. 1), with upper end portions of the conductors WHi, WH.sub.2, WH.sub.3, WH.sub.4, and WH.sub.5 being received in the well area 44 prior to connection of such upper conductor end portions to the terminal block 46 as subsequently described herein.

[0034] As schematically depicted in FIG. 2, the lower end of conductor WH.sub.i is connected to the lower thermostat power supply terminal 64; the lower end of conductor WH.sub.2 is connected to the upper thermostat power supply terminal 50; the lower end of conductor WH.sub.3 is connected to the upper thermostat power supply terminal 52; the lower end of conductor WH.sub.4 is connected to the upper thermostat switch contact 62; and the lower end of conductor WH.sub.5 is connected to the lower thermostat power supply terminal 66.

[0035] Turning now to FIG. 3, the terminal block portion 46 of the junction box 48 has a line side 46a with terminals L.sub.A, L.sub.B, Lc, L.sub.D, and L.sub.E, and a water heater side 46b with terminals H.sub.A, H.sub.B, Hc, H.sub.D, and H.sub.E electrically coupled to the line side terminals L.sub.A, LB, Lc, L.sub.D, and L.sub.E as indicated by the dashed lines. With the junction box 48 either operatively mounted on the top end of the water heater 10 as schematically shown in FIG. 1 or attached or placed in an enclosure at the front of the water heater, the control mode of the water heater's upper and lower heating elements 18 and 20 may be selectively varied simply by adding or reconfiguring various wiring connections in the terminal block 46 as will now be described.

[0036] In a preferred embodiment, on the water heater side 46b of the terminal block 46 wiring harness conductor WH.sub.i is connected to terminal H.sub.B, wiring harness conductor WH.sub.2 is connected to terminal Elc, wiring harness conductor WH.sub.3 is connected to terminal H.sub.D, wiring harness conductor WH.sub.4 is connected to terminal H.sub.A, and wiring harness conductor WH.sub.5 is connected to terminal HE. Representatively, there are seven different dual heating element operational control modes available for the water heater 10 simply by adding wiring connections to the terminal block 46, and without changing the wiring interconnection between the thermostats 38 and 40, replacing either thermostat with another type of thermostat, or changing the wiring interconnection from the thermostats 38 and 40 to the terminal block 46. The seven heating element operational control modes, and the terminal block wiring configurations that yield them, are as follows:

Dual Independent Branch Circuit Installation Mode

[0037] As schematically depicted in FIG. 4, to provide the water heater 10 with a dual independent branch circuit installation for its upper and lower electric resistance type upper and lower heating elements 18 and 20, first power supply conductors 88 and 90 are respectively connected to the terminal block line side terminals Lc and L.sub.D, and second power supply conductors 92 and 94 are respectively connected to the terminal block line side terminals L.sub.B and LE.

Single Phase Simultaneous Dual Element Control Mode

[0038] As schematically depicted in FIG. 5, to provide the water heater 10 with a single phase, simultaneous operation of its upper and lower electric resistance type upper and lower heating elements 18 and 20, single phase power supply conductors 96 and 98 are respectively connected to the terminal block line side terminals Lc and L.sub.D. On the water heater side 46b of the terminal block 46, terminals H.sub.B and H.sub.e are connected such as with additional wiring or a jumper, and terminals H.sub.D and H.sub.E are connected such as with additional wiring or a jumper.

Single Phase Non-Simultaneous Dual Element Control Mode

[0039] As schematically depicted in FIG. 6, to provide the water heater 10 with a single phase, non-simultaneous operation of its upper and lower electric resistance type upper and lower heating elements 18 and 20, single phase power supply conductors 100 and 102 are respectively connected to the terminal block line side terminals Lc and L.sub.D. On the water heater side 46b of the terminal block 46, terminals H.sub.A and H.sub.B are connected such as with additional wiring or a jumper, and terminals H.sub.D and H.sub.E are connected such as with additional wiring or a jumper.

Single Phase Non-Simultaneous Dual Element Control Mode with 4 Wire Outlet Operation

[0040] As schematically depicted in FIG. 7, to provide this dual element operational control mode, single phase power supply conductors 104 and 106 are respectively connected to the terminal block line side terminals Lc and L.sub.D. On the water heater side 46b of the terminal block 46, terminals H.sub.D and H.sub.E are connected such as with additional wiring or a jumper. Additionally, if off peak metering is desired, an off peak meter or timer is connected to terminals L.sub.A and L.sub.B on the line side 46a of the terminal block.

Single Phase Non-Simultaneous Dual Element Control Mode with 3 Wire Outlet Operation

[0041] As schematically depicted in FIG. 8, to provide this dual element operational control mode, single phase power supply conductors 110 and 112 are respectively connected to the terminal block line side terminals Lc and L.sub.D. On the water heater side 46b of the terminal block 46, terminals H.sub.A and H.sub.B are connected such as with additional wiring or a jumper. If off peak metering is desired, an off peak meter or timer is connected to terminal L.sub.E.

Three Phase Simultaneous Dual Element Control Mode

[0042] As schematically depicted in FIG. 9, to provide this dual element operational control mode, three phase power supply conductors 116, 118, and 120 are respectively connected to the terminal block line side terminals Lc, L.sub.D, and L.sub.E. On the water heater side 46b of the terminal block 46, terminals H.sub.B and H.sub.e are connected such as with additional wiring or a jumper.

Three Phase Non-Simultaneous Dual Element Control Mode

[0043] As schematically depicted in FIG. 10, to provide this dual element operational control mode, three phase power supply conductors 122, 124, and 126 are respectively connected to the terminal block line side terminals Lc, L.sub.D, and L.sub.E. On the water heater side 46b of the terminal block 46, terminals H.sub.A and H.sub.B are connected such as with additional wiring or a jumper.

[0044] As can readily be seen from the foregoing, the water heater 10 may uniquely be field-converted selectively among its seven representative dual heating element operational control modes simply by appropriately altering the electrical connections in the terminal block 46. In contrast to conventionally constructed dual element electric water heaters, there is simply no need to either (1) replace either of the upper and lower thermostats 38 and 40 with another type of thermostat, or (2) change the wiring connections to the two thermostats or from the thermostats to the terminal block. This advantageously makes the representatively listed seven dual heating element operational control modes available with the single illustrated variant of the dual element electric water heater 10. In addition, as can readily be seen from the foregoing preferred embodiments, the connections of terminals in the terminal block 46 are to adjacent terminals and can be made using connections such as additional wiring or a jumper of a uniform size. While the present invention has been illustratively incorporated in an electric water heater, it will be readily appreciated that principles of the invention could also be incorporated in dual element liquid heating devices of other types if desired. It will additionally be appreciated that while the terminals H.sub.A, H.sub.B, Hc, H.sub.D, and H.sub.E are representatively connectable in selectively variable manners using jumpers or other similar connectors to a terminal block portion of a junction box, the outer ends of the wiring harness conductors WH.sub.i, WH.sub.2, WH.sub.3, WH.sub.4, and WH.sub.5 could alternatively be variably connected to an external electrical power source in a variety of other manners, including, for example, the use of connections between L.sub.A, L.sub.B, Lc, L.sub.D, and L.sub.E, if desired.

[0045] The foregoing detailed description is to be clearly understood as being given by way of illustration and example, the spirit and scope of the present invention being limited solely by the appended claims.