Abstract: An evaporator coil defrost control system for a refrigeration system comprising refrigerant compression means, a condenser coil, an evaporator coil, and an electric motor operated fan positioned adjacent to said evaporator coil and adapted, when energized, to blow air through said evaporator coil, said defrost control system comprising: strain sensing means connected to said fan blades and adapted to measure force applied to said fan and to produce a signal indicative of said measured force; controller means connected to said strain sensing means to receive the signal therefrom and having operative connections to said system, said controller being adapted to place said system in a defrost mode of operation upon said signal of said strain sensing means having a characteristic indicative of a significant frost build-up on said evaporator coil.

Abstract: A control system for a reverse cycle refrigeration system for controlling the defrosting of the outdoor coil thereof on a cost effective basis; the control system comprising a controller means receiving inputs indicative of the temperature of the outdoor coil, and the operation of the compressor means; the controller means having a timing function which is initiated upon the outdoor coil temperature being at or below a preselected value and the compressor means being operated; the duration of the timing function being determined on a substantially continuous basis as a function of the magnitude of the outdoor coil temperature; and the controller means having an operative connection to the system so as to, upon completion of the timing function, place the reverse cycle refrigeration system into an outdoor coil defrost mode of operation.

Abstract: A compressor fault detection and control system for a reverse cycle refrigeration system for detecting faulty compressor operation and for controlling the system in response to the detection of a fault by inhibiting the compressor and for providing a fault indication, the control system comprising a controller means receiving inputs indicative of the outdoor coil temperature, the temperature of the compressor discharge refrigerant, and an output indicative of a demand from an enclosed space temperature sensing means for heating or cooling of the enclosed space. The controller means also includes timing means and means for comparing the value of the compressor discharge temperature and the value of the outdoor coil temperature.

Abstract: A compressor fault detection and control system for a reverse cycle refrigeration system for detecting faulty compressor operation and for controlling the system in response to the detection of a fault by inhibiting the compressor and for providing a fault indication, the control system comprising a controller means receiving inputs indicative of the outdoor air temperature, the temperature of the compressor discharge refrigerant, and an output indicative of a demand from a building temperature sensing means for heating or cooling of the building. The controller means also includes timing means and means for comparing the value of the compressor discharge temperature and the value of the outdoor air temperature.

Abstract: A compressor crankcase low differential temperature detection and control system for a reverse-cycle refrigeration system for detecting an abnormally low temperature crankcase and for controlling the system in response to such fault detection by inhibiting the operation of the compressor and for providing a fault indication.

Abstract: A compressor start fault detection and control system for a reverse cycle refrigeration system for detecting faulty compressor startup operation and for controlling the system in response to the detection of a fault by inhibiting the compressor and for providing a fault indication, the control system comprising a controller means receiving an input indicative of the temperature of the compressor discharge refrigerant and an output indicative of a demand from a building temperature sensing means for heating or cooling of the building.

Abstract: A loss of refrigerant and/or high discharge temperature detection and control system for a reverse cycle refrigeration system by providing a fault indication whenever the temperature of the compressor discharge refrigerant is at or above a predetermined value (which value is a function of the magnitude of the outdoor air temperature) and which functions further by inhibiting the operation of the compressor of the reverse cycle refrigeration system whenever the temperature of the refrigerant at the compressor discharge exceeds a predetermined value above which the compressor would be damaged if it continued to operate.

Abstract: An improper or wrong operational mode fault detection and control system for a reverse cycle refrigeration system for detecting faulty operation, i.e., operation in the cooling mode when heating is desired or in the heating mode when cooling is requested, and for controlling the system in response to the detection of a fault by inhibiting the compressor and for providing a fault indication, the control system comprising a controller means receiving inputs indicative of the outdoor air temperature, the temperature of the outdoor heat exchanger coil refrigerant, and an output indicative of a demand from a building temperature sensing means for heating or cooling of the building. The controller means also includes timing means and means for comparing the value of the outdoor heat exchanger coil refrigerant temperature and the value of the outdoor air temperature.

Abstract: A control system for a reverse cycle refrigeration system for controlling the defrosting of the outdoor coil thereof on a cost effective basis; the control system comprising a controller means receiving inputs indicative of the outdoor air temperature, the temperature of the outdoor coil, and the operation of the compressor means; the controller means having a timing function which is initiated upon the outdoor coil temperature being at or below a preselected value and the compressor means being operated; the duration of the timing function being determined on a substantially continuous basis as a function of the magnitude of the outdoor air temperature; and the controller means having an operative connection to the system so as to, upon completion of the timing function, place the reverse cycle refrigeration system into an outdoor coil defrost mode of operation.

Abstract: A control system that provides a safety limit and temperature control for an oil preheater used with oil burners that burn viscous grades of fuel oil. The control incorporates a first temperature sensor for control of a fuel oil heater and a second temperature sensing means to provide for a safe start check of an oil burner.The start is allowed only if the temperature of the oil is at or above the temperature required for proper operation of the fuel burner.

Abstract: A mounting plate adapted to mount a transformer on an electric circuit enclosure. The mounting plate is provided with a dual function knockout arrangement so that the transformer to be mounted can either be surface mounted with different types of mounting means, or can be recessed into the plate by the removal of the entire knockout portion.