Installation
I/O Wiring & Sequence
MSV127 – RT ECON
Economizer
The controller can be configured with the economizer option to take advantage of free cooling. The two Control Types of that
can be configured are Off-Auto or Modulating control.
Dry Bulb
The economizer is enabled to utilize free cooling when there is a call for cooling and the outside air temperature is less than
the OAT Econo Authorization setpoint.
When the control type is set to Off-Auto, and economizer is enabled, the output will energize the manufacturers equipment
economizer control.
When the control type is set for Modulating, the controller will modulate the outside air damper from minimum to 100% to
maintain the Minimum Supply Setpoint (55°F/13°C) at 100% demand call. When the demand call is 0%, the economizer will
be set Off or Modulated to maintain the Neutral Supply Setpoint (68°F/20°C). This sequence requires an Outdoor Air Sensor
only and setting the OAT Econo Authorization setpoint at a value higher than the OAT [ex. OAT Econo Authorization setpoint =
70 °F and OAT = 62 then Economizer will operate] Configure the Economizer control type and output location.
Enthalpy
If the calculated enthalpy is LESS than the enthalpy setpoint, the economizer will run in free cooling mode when it receives a
call for cooling and our sequence allows compressor operation during economizer mode which can be a way to save energy
when we cool the outdoor air instead of the return air. This sequence requires an Outdoor Air sensor, a Supply Air sensor, a
Mixed Air sensor and a Humidity sensor location in Econo Config and Control Sensor physical location in Hum and
Dehumid Config. The OAT Econo Authorization setpoint must be a value higher than the OAT [ex. OAT Econo Authorization
setpoint = 70 °F and OAT = 62 then Economizer will operate] Configure the Economizer control type and output location to
run the Enthalpy Economizer sequence.
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