Temperature control system with multiple thermostats

Claim 2

A control arrangement for regulating operation of a cooling system which discharges air into a space and receives return air from the space, which control arrangement comprises: a first thermostat disposed to provide a first temperature signal indicative of the discharge air temperature; a second thermostat, disposed to provide a second temperature signal indicative of the return air temperature; a temperature set unit, adjustable to provide a set signal indicating the desired temperature of the space; a selection circuit, connected to receive both the set signal and a first reference signal, which selection circuit completes an operating circuit for the first thermostat when the value of the set signal is less than the value of the first reference signal, and completes an operating circuit for the second thermostat when the value of the set signal is greater than the value of the first reference signal; and a comparator circuit, connected to receive both the set signal and the temperature signal from the energized one of the thermostats, and to provide a regulating signal, related to the difference between the set signal and the temperature signal from the energized thermostat, to regulate associated equipment.

Claim 3

A control arrangement as claimed in claim 1, and further comprising a heat override circuit, connected to receive both the set signal and a second reference signal, operative to provide a lock-out signal to prevent operation of associated heating equipment when the temperature called for by the set signal is below the value of the temperature represented by the second reference signal.

Claim 4

A control arrangement for regulating operation of a cooling system which discharges air into a space and receives return air from the space, which control arrangement comprises: a first Thermistor disposed to provide a first temperature signal indicative of the discharge air temperature; a second Thermistor, disposed to provide a second temperature signal indicative of the return air temperature; a temperature set potentiometer, adjustable to provide a set signal indicating the desired temperature of the space; a selection circuit, including a voltage level detector connected to receive both the set signal and a first reference signal, a first transistor connected to complete an operating circuit for the first Thermistor when the value of the set signal is less than the value of the first reference signal, and a second transistor connected to complete an operating circuit for the second Thermistor when the value of the set signal is greater than the value of the first reference signal; and a comparator circuit, connected to receive both the set signal and the temperature signal from the energized one of the Thermistors, and to provide a regulating signal, related to the difference between the set signal and the temperature signal from the energized Thermistor, to regulate associated equipment.

Claim 5

A control arrangement for regulating operation of a cooling system which discharges air into a space and receives return air from the space, which control arrangement comprises: a first Thermistor disposed to provide a first temperature signal indicative of the discharge air temperature; a second Thermistor, disposed to provide a second temperature signal indicative of the return air temperature; a temperature set potentiometer, adjustable to provide a set signal indicating the desired temperature of the space; a selection circuit, including a voltage level detector connected to receive both the set signal and a first reference signal, a first transistor connected to complete an operating circuit for the first Thermistor when the value of the set signal is less than the value of the first reference signal, and a second transistor connected to complete an operating circuit for the second Thermistor when the value of the set signal is greater than the value of the first reference signal; and a comparator circuit, connected to receive both the set signal and the temperature signal from the energized one of the Thermistors, and to provide a regulating signal, related to the difference between the set signal and the temperature signal from the energized Thermistor, to regulate associated equipment.

Claim 6

A control arrangement for regulating operation of a cooling system which discharges air into a space and receives return air from the same space, including first and second thermostats disposed to provide temperature signals indicating the discharge and return air temperature, a temperature set unit providing a set signal to indicate the desired space temperature, a selection circuit completing an operating circuit to only one of the thermostats as a function of the set signal and a first reference signal, a comparator circuit receiving the set signal and the temperature signal from the energized thermostat to provide on a common line a regulating signal which is a function of the difference between the set signal and the actual temperature signal from the energized thermostat, and at least two cooling control stages, each having an input portion coupled to the common line, and each having an output circuit individually coupled to different cooling components, to bring on one of the different cooling components at different amplitude levels of the regulating signal on the common line.

Claim 7

A control arrangement for regulating operation of a cooling system which discharges air into a space and receives return air from the same space, including first and second thermostats disposed to provide temperature signals indicating the discharge and return air temperature, a temperature set unit providing a set signal to indicate the desired space temperature, a selection circuit completing an operating circuit to only one of the thermostats as a function of the set signal and a first reference signal, a comparator circuit receiving the set signal and the temperature signal from the energized thermostat to provide on a common line a regulating signal which is a function of the difference between the set signal and the actual temperature signal from the energized thermostat, and at least two cooling control stages, each having an input portion coupled to the common line, and each having an output circuit individually coupled to different cooling components, to bring on one of the different cooling components at different amplitude levels of the regulating signal on the common line.

Claim 8

A control arrangement for regulating operation of a cooling system by comparing a temperature set signal with an actual temperature signal and providing a regulating signal, related to the difference between the set signal and the actual temperature signal to regulate cooling equipment including at least two compressors through a plurality of cooling control stages, which control arrangement comprises: a common line connected to receive the regulating signal; a first cooling control stage, having a first input connection coupled to the common line and a second input connection connected to receive a first reference signal, to provide an actuating output signal when the regulating signal exceeds the first reference signal and bring the first compressor on the line; a second cooling control stage, having a first input connection coupled to the common line and a second input connection coupled to receive a second reference signal, to provide an actuating output signal when the regulating signal exceeds the second reference signal and bring the second compressor on the line; and a first time-delay circuit, coupled to said first cooling control stage, effective to maintain said first controlling stage in the off condition for a predetermined minimum time interval after the regulating signal on the common line has decreased below the value of the first reference signal, to avoid excess cycling of the first compressor.

Claim 9

A control arrangement for regulating operation of a cooling system by comparing a temperature set signal with an actual temperature signal and providing a regulating signal, related to the difference between the set signal and the actual temperature signal to regulate cooling equipment including at least two compressors through a plurality of cooling control stages, which control arrangement comprises: a common line connected to receive the regulating signal; a first cooling control stage, having a first input connection coupled to the common line and a second input connection connected to receive a first reference signal, to provide an actuating output signal when the regulating signal exceeds the first reference signal and bring the first compressor on the line; a second cooling control stage, having a first input connection coupled to the common line and a second input connection coupled to receive a second reference signal, to provide an actuating output signal when the regulating signal exceeds the second reference signal and bring the second compressor on the line; and a first time-delay circuit, coupled to said first cooling control stage, effective to maintain said first controlling stage in the off condition for a predetermined minimum time interval after the regulating signal on the common line has decreased below the value of the first reference signal, to avoid excess cycling of the first compressor.

Claim 10

A control arrangement as claimed in claim 5, and further comprising a second time-delay circuit, coupled to said second cooling control stage, effective to prevent said second cooling control stage from providing an actuaTing output signal for a predetermined minimum time interval after the regulating signal on the common line exceeds the value of the second reference signal, to prevent simultaneous energization of the first and second compressors and obviate a large drain on the power supply.