Air conditioning and refrigeration controls and components integrate into cooling systems and manage the operation and sequencing of the various system components. Pressure controls for air conditioning and refrigeration monitor and regulate refrigerant pressures to ensure optimal system operation. Refrigeration cold controls monitor and regulate the operation of refrigeration equipment to maintain desired temperatures. Defrost thermostats prevent frost buildup and keep items cold during defrost cycles. Potential relays safeguard the motor and start capacitors by disconnecting the starting capacitor when the motor is running. Compressor hard start kits provide additional power to help start high-powered components such as compressors. Heat pump reversing valves and solenoid coils control the flow of refrigerant in a reversible heat pump. Refrigeration appliance temperature controls regulate temperatures in cooling appliances.