Ranco EcoCool E7 Series - Page 8

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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, the
compressor or solenoid valve is energized until the controlled space temperature is equal to or less than the Cut-Out warm setpoint. Similarly, when the
adjustment 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 and
de-energized when the temperature is equal to or below the Cut-Out cold setpoint. For adjustment knob positions between warm and cold, the controller
interpolates 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 seconds
after adjustment. Because the four setpoints are configured independently, the differential can remain constant or change linearly between the cold and
warm settings.
Refer to the graphs below for various setting scenarios.
The compressor can be protected against short cycling by three time delays. The Compressor Minimum Off Time at Start delay begins counting down
when 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 not
count down while the adjustment knob is in the OFF position. When the compressor is powered on the Compressor Minimum On Time delay begins
counting down. The compressor is not powered off by the controller before this delay expires regardless of the control temperature or setpoint. However, if
the adjustment knob is rotated to OFF the controller and compressor are immediately powered off. When the controller powers off the compressor, the
Compressor Minimum Off Time delay begins counting down. The compressor is not powered on before this timer expires regardless of control temperature
or setpoint.
TIP: An excessive Compressor Minimum On Time or Compressor Minimum Off Time can force the temperature past an alarm threshold and trigger a
temperature alarm.
Type E7 EcoCool™ Electronic Temperature and Defrost Controllers
©2008 Invensys Controls All rights reserved.
DRAFT VERSION
Cut-In
Cut-Out
Warm
Position
Setpoints
Cold
Position
Setpoints
T
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Adjustment Knob Setpoint Range
Variable Differential
Cut-In
Cut-Out
Warm
Position
Setpoints
Cold
Position
Setpoints
T
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m
p
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r
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Adjustment Knob Setpoint Range
Wide Differential
Cut-In
Cut-Out
Warm
Position
Setpoints
Cold
Position
Setpoints
T
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p
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Adjustment Knob Setpoint Range
Narrow Differential
Cut-In
Cut-Out
Warm
Position
Setpoints
Cold
Position
Setpoints
T
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p
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Adjustment Knob Setpoint Range
Constant Cut-In
Cut-In
Warm
Position
Setpoints
Cold
Position
Setpoints
T
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p
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Adjustment Knob Setpoint Range
Fixed Setpoint
Cut-Out