GB2069778A - Switching unit for use with electric domestic immersion heaters - Google Patents

Abstract

A control unit for domestic tank installed immersion heaters includes a self-latching relay (R1) connected in series with the immersion heater (H) and thermostat (TL). When the thermostat opens, the relay de-energises and will prevent further heating until the relay is manually reset by moving a switch momentarily from "one heat" to "auto" position. The unit may also be switched to automatic operation, so that, constant supply to the heater will be provided whenever the thermostat demands. Neon indicator lamps are provided. This unit overcomes forgetfulness to switch the heater off, and thereby reduces electricity consumption. <IMAGE>

Description

SPECIFICATION Electricity saving unit for use with electric domestic immersion heaters for energy economy Controller is designed to replace existing switches mounted locally to domestic 3 k.w. immersion heaters installed near hot water tanks. The unit will accept the existing system of thermostat control and heater, and connect its circuit direct with 2 wire plus earth control.

The unit will isolate supply to the immersion heater after the preset thermostat temperature has been reached and will not restore supply until the unit has been reset to heat again.

Present systems continue to heat and switch under demand of the thermostat. This unit will isolate and economise on electricity by locking supply off after temperature is reached.

The unit will incorporate a double pole switch for full isolation of the main supply. A single pole switch will provide either Auto Heat or One Heat through the circuit. A relay (current operated) will be connected in series with the switch, and in series with the thermostat and heater.

The relay will de-energise after the immersion thermostat has opened and will not reclose until the single pole switch is operated to Auto and back to One Heat. The heater will operate, providing the thermostat demands heat.

The unit will be fitted with a Red Neon light to indicate MAINS ON when the double pole switch is operated. The unit will also be fitted with a Green Neon light to indicate HEAT ON, to cover both Auto and One Heat conditions.

The complete wiring circuit, including relay coil, will be capable of passing 15 amps. with no overheating.

1. Visible indication by means of Neon indicators when the unit is switched on, also when electricity is being used for water heating purposes.

2. The facility is provided to enable the userto select either a one heat period or a constant auto controlled heat under the control of the immersion heater thermostat, by means of a selector switch.

3. The lay-out of the switches and indicator lights on the front of the unit leaves the user in no doubt whatsoever as to what is happening.

4. The components used are all standard stock items, easily available should there be any need to replace.

5. The relay is capable of energising in series with the immersion heater, rather than in parallel. A parallel operation would require three control links, plus an earth cable. This unit has the advantage of being two control links, plus the earthing cable.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Electricity saving unit for use with electric domestic immersion heaters for energy economy Controller is designed to replace existing switches mounted locally to domestic 3 k.w. immersion heaters installed near hot water tanks. The unit will accept the existing system of thermostat control and heater, and connect its circuit direct with 2 wire plus earth control. The unit will isolate supply to the immersion heater after the preset thermostat temperature has been reached and will not restore supply until the unit has been reset to heat again. Present systems continue to heat and switch under demand of the thermostat. This unit will isolate and economise on electricity by locking supply off after temperature is reached. The unit will incorporate a double pole switch for full isolation of the main supply. A single pole switch will provide either Auto Heat or One Heat through the circuit. A relay (current operated) will be connected in series with the switch, and in series with the thermostat and heater. The relay will de-energise after the immersion thermostat has opened and will not reclose until the single pole switch is operated to Auto and back to One Heat. The heater will operate, providing the thermostat demands heat. The unit will be fitted with a Red Neon light to indicate MAINS ON when the double pole switch is operated. The unit will also be fitted with a Green Neon light to indicate HEAT ON, to cover both Auto and One Heat conditions. The complete wiring circuit, including relay coil, will be capable of passing 15 amps. with no overheating. CLAIMS

1. Visible indication by means of Neon indicators when the unit is switched on, also when electricity is being used for water heating purposes.

2. The facility is provided to enable the userto select either a one heat period or a constant auto controlled heat under the control of the immersion heater thermostat, by means of a selector switch.

3. The lay-out of the switches and indicator lights on the front of the unit leaves the user in no doubt whatsoever as to what is happening.

4. The components used are all standard stock items, easily available should there be any need to replace.

5. The relay is capable of energising in series with the immersion heater, rather than in parallel. A parallel operation would require three control links, plus an earth cable. This unit has the advantage of being two control links, plus the earthing cable.