An electronic thermostat includes selectable multiple predetermined temperature programs of desired temperatures over a repetitive time cycle. A manually operable temperature program selector enables recall of a desired temperature for a particular time from a temperature program memory in accordance with the selected predetermined temperature program. This desired temperature is compared to the ambient temperature in order to generate control signals for a temperature modifying device. In the preferred embodiment, the multiple temperature programs each consist of digital signals indicative of either a normal temperature or a set-back temperature. A separate operator actuable set point device determines the normal temperature. When the normal temperature is indicated, the thermostat controls the temperature modifying load to restore the selected normal temperature. When the set-back temperature is indicated, the thermostat controls the temperature modifying load to restore a temperature which is a predetermined number of degrees offset from the selected normal temperature. The set-back temperature is lower in a heating mode and higher in a cooling mode enabling reduced energy consumption in the temperature modifying device. In the preferred embodiment, the number of degrees of the offset is selectable via an operator control.

Electronic programmable thermostat

Methods and devices for controlling multi-stage boiler systems. In one illustrative embodiment, the number of stages to be used is determined in a staging control sequence in response to a heating load, and in some cases, the individual stages are modulated to meet a heating load. In some embodiments, the staging control sequence may include observation of both heating load and the rate of change of the heating load. In another illustrative embodiment, the staging control observes compares a measured temperature to a setpoint and monitors changes in the measured temperature to make staging decisions. Various control methods are also provided to help achieve improved stability and efficiency, as desired.

Multi-stage boiler staging and modulation control methods and controllers

An improved device and corresponding method for warning of deterioration of a starter mechanism in which a motor is powered by a battery to start a combustion engine, prior to failure of the starter mechanism to enable starting of the engine. Featuring the addition of at least one noise and/or vibration sensor, at least one corresponding noise and/or vibration level tester, a logic circuit, and a delay mechanism, to a device and method including a timer responsive to activation of the starter mechanism to time a given time interval, a voltage level tester for measuring a voltage across the battery at the end of the given time interval, a counter for performing an incremental count of occasions on which the voltage is below a given level, and an alarm unit for providing a warning signal when the incremental count is greater than a given number. The logic circuit causes activation of the alarm unit to provide an additional warning signal of starter mechanism deterioration following engine turn-off, upon fulfillment of an `AND` logic operation by receiving (i) a first signal from the noise and/or vibration level tester less than a pre-determined threshold level indicating engine turn-off, and (ii) a delayed second signal from the counter that the incremental count is greater than the given number indicating sudden drop in battery voltage less than the given level following the given time interval. The delay mechanism enables proper synchronization of activation of the logic circuit and the alarm unit. A simpler embodiment has no counter, but includes a latch circuit for registering, storing, and sending to the logic circuit the delayed second signal of drop in battery voltage from the timer.

Device and method for warning of vehicle battery deterioration

A method and apparatus for controlling the temperature of a space. The actual heat load for a space under the conditions prevailing at a time is determined based upon information available to a temperature sensor. The average heating/cooling percentage rate for relatively short duty cycles is adjusted based on this information whereby the actual heating/cooling load during this duty cycle interval may be approximately matched. The percentage rate may be overridden in the event an abnormal temperature situation exists. The method and apparatus of this invention has particular application when utilized with radiant heaters.

Apparatus and method for controlling the temperature of a space

The method for adjusting the temperature set point of a HVAC unit and activating and deactivating the HVAC unit utilizes one sensor to periodically determine the thermostat activity in a controlled environment and a second sensor to measure the temperature of a transfer medium output from said HVAC system. A microprocessor receives, stores and processes information from the two sensors and is connected to and controls the HVAC unit. The first sensor records thermostat activity for the controlled environment at set intervals over a defined time period and they are stored in the microprocessor. An actual HVAC demand model for said controlled environment is created by the microprocessor, based on said recorded thermostat activity. The actual HVAC demand model is compared to an ideal HVAC demand model and a temperature change factor is calculated. Then, the optimum temperature set point for said HVAC unit is determined, based on said temperature change factor. The microprocessor adjusts the actual temperature set point of the HVAC unit to the optimum temperature set point. In addition, the microprocessor continuously monitors the temperature of the transfer medium of said HVAC unit. This temperature is compared to the temperature set point for the HVAC unit. The microprocessor generates a signal to the HVAC unit for activating it when the temperature of the transfer medium deviates from the temperature set point by more than the temperature set point range differential. The HVAC unit is turned off by the microprocessor when the temperature of the transfer medium returns to the temperature set point.

Method for controlling hvac units

A multi-stage condition control system of the time proportional type is shown. The control system utilizes a counting means as part of the anticipation for system control. The counting means counts during the time the control system is within its proportional band. When the control system moves outside of the proportional band, the counting stops. A count detection circuit senses the absence of counts thereby indicating that the system is outside of the proportional band. The absence of counts is then used to increase or decrease multiple stages of condition control equipment to bring the system back within the proportional band.

Multi-stage controller

Circuitry associated with a self-contained abnormal condition sensing and alarm annunciating unit for supervising or monitoring leads interconnecting a plurality of such units and for responding to an open circuit condition of such leads so as to actuate an annunciator in a distinctive fashion to signal the open circuit condition.

Apparatus for supervising leads interconnecting a plurality of self-contained abnormal condition sensing and alarm annunciating units

OF THE DISCLOSURE A time proportional control means, shown as a temperature control system, utilizes an expanded time constant arrangement with a unidirectional type of digital counter. The control system also utilizes a pulse gener-ating means that is linked to the set point control for the system. Any substantial change of the set point causes the pulse generating means to generate pulses that are used by a pulse responsive circuit to insure that the counter for the system is adjusted to cause the output of the system to correspond with the new set point position.

Condition control system with special set point means

A proportional temperature control system using a linear time delay circuit provides an output voltage that is similar to the output voltage of a thermostat but delayed in time. The delay circuit is a linear rate time delay system that compares a called for voltage shift at its input to the output voltage of an integrator circuit to provide a substantially linear rate of time delay. The comparator circuit and the integrator circuit are separated by a limiter so that regardless of the amount of the initial offset in voltage at the comparator, the rate of integration is always maintained the same.

Proportional temperature control system incorporating a linear delay

A thermostat with a single control to establish the quantity of set back during heating and set up during cooling.

John L. Kabat

Papers

Multi-stage controller

Apparatus for supervising leads interconnecting a plurality of self-contained abnormal condition sensing and alarm annunciating units

Condition control system with special set point means

Proportional temperature control system incorporating a linear delay

Thermostat with improved temperature sensing circuit