Model DN-EM is an energy flow monitor intended for applications in energy transfer and in heating/cooling systems such as heating and cooling loops, heat recovery applications, condensate recovery applications, efficiency measurement/verification systems, solar/geothermal systems, and other applications. The energy flow monitors are designed for flow ranges from 0.9 to 22.5 gpm, ½- or ¾-inch piping, and ambient temperatures of -15° to 85°C. They calculate energy use based on the mass volume of liquid passing through the system and the difference in temperature between the supply and return lines. The volume of liquid is measured by means of a pulse-generating vortex flow transmitter. An RTD sensor built into the flowmeter measures temperature at the meter, and the remote temperature is measured by means of a precision RTD sensor mounted in a pipe tee. A scaled pulse output is provided and can be configured to report volume flow rate, mass flow rate, or energy total. Modbus 485 communications provide an interface with building automation, process control, or other monitoring systems. Model DN-EM energy flow monitors utilize nonvolatile memory that records flow and energy. Readings are updated every 10 minutes except when flow, mass, or energy totals are read. These values are true current values with the last stored value being added to the current accumulated value when the applicable register is read. Readings of flow rate, mass flow, energy rate, total flow, total energy, and temperature are available in a variety of units.