Ranco Eco-Cool E71R/E72R Temperature and ... - icemeister.net

When the adjustment knob is set to the warm position and the controlled space temperature is equal to or greater than the Cut-In warm setpoint, thecompressor or solenoid valve is energized until the controlled space temperature is equal to or less than the Cut-Out warm setpoint. Similarly, when theadjustment knob is set to cold, the compressor or solenoid valve is energized when the temperature is equal to or greater than the Cut-In cold setpoint andde-energized when the temperature is equal to or below the Cut-Out cold setpoint. For adjustment knob positions between warm and cold, the controllerinterpolates the cut-in and cut-out setpoints from the four configured setpoints.The optional display changes from the control temperature to the Cut-Out setpoint during adjustment and reverts to the control temperature three secondsafter adjustment. Because the four setpoints are configured independently, the differential can remain constant or change linearly between the cold andwarm settings.Refer to the graphs below for various setting scenarios.WarmPositionSetpointsNarrow DifferentialWarmPositionSetpointsWide DifferentialCut-InTemperatureCut-InTemperatureCut-OutColdPositionSetpointsCut-OutColdPositionSetpointsAdjustment Knob Setpoint RangeAdjustment Knob Setpoint RangeWarmPositionSetpointsConstant Cut-InWarmPositionSetpointsVariable DifferentialTemperatureCut-InCut-OutColdPositionSetpointsTemperatureCut-InCut-OutColdPositionSetpointsDRAFT VERSIONAdjustment Knob Setpoint RangeAdjustment Knob Setpoint RangeWarmPositionSetpointsFixed SetpointTemperatureCut-InCut-OutColdPositionSetpointsAdjustment Knob Setpoint RangeThe compressor can be protected against short cycling by three time delays. The Compressor Minimum Off Time at Start delay begins counting downwhen the controller is powered on. The compressor cannot be powered on before this delay expires. If the ON/OFF function is enabled, the timer does notcount down while the adjustment knob is in the OFF position. When the compressor is powered on the Compressor Minimum On Time delay beginscounting down. The compressor is not powered off by the controller before this delay expires regardless of the control temperature or setpoint. However, ifthe adjustment knob is rotated to OFF the controller and compressor are immediately powered off. When the controller powers off the compressor, theCompressor Minimum Off Time delay begins counting down. The compressor is not powered on before this timer expires regardless of control temperatureor setpoint.TIP:An excessive Compressor Minimum On Time or Compressor Minimum Off Time can force the temperature past an alarm threshold and trigger atemperature alarm.Type E7 EcoCool Electronic Temperature and Defrost Controllers©2008 Invensys Controls All rights reserved.8