Kolpak A421 Manuel D'installation, De Fonctionnement Et D'entretien page 12

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Anti-short cycle delay (ASd) Select the minimum time that the output relay remains off (de-energized) before the
next on-cycle can start. The ASd interval overrides any load demand (On) and does not allow the output relay to go on
until the selected ASd interval has elapsed. See the following figure.
• Anti-short cycle delay is typically used for refrigeration applications so that the system pressure can equalize before
restarting the compressor.
Note: When the ASd value is greater than 0, the delay interval initiates every time that the A421 Control is powers on and
every time that an off-cycle begins. When the ASd interval is activated, the temperature sensed at the A99 sensor and
the parameter code ASd flash alternately on the LCD. You can set the ASd interval from from 0 minutes to 12 minutes,
in 1 minute increments.
Sensor Failure mode (SF) Select whether the control's output relay operates as energized or de-energized in the event
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of a sensor or sensor wiring failure. When the control detects a sensor circuit failure, the output relay operates in the
selected sensor failure mode. The LCD flashes SF and OP if the sensor circuit is open or SF and SH if the sensor circuit is
shorted.
Temperature Units (Un) Select the preferred temperature scale for your application. Select either the Fahrenheit (°F)
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or Celsius (°C) temperature scale.
Note: After you change the temperature units value (Un), confirm that the temperature values for the other parameter
codes are still correct for your application.
Low Temperature Stop (LtS) Select the lowest temperature value that the On/OFF control band can be adjusted to
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when control adjustment is restricted.
• High Temperature Stop (HtS) Select the highest temperature value that the On/OFF control band can be adjusted to
when control adjustment is restricted.
• Restricted Adjustment mode The HtS and LtS values define the restricted adjustment temperature range and are
enforced only when the A421 control is set to the restricted adjustment mode. See Restricting user adjustment.
Note: It is best practice to leave HtS and LtS at their default values, unless you intend to use the restricted adjustment
mode.
Note: If you use the Temperature Setback feature in the Restricted Adjustment Mode, the effective On and OFF setback
values (On + tBs and OFF + tBs) can be greater than the selected HtS value or less than the selected LtS value.
Temperature Setback (tSb) Select a temperature value for setting back the On and OFF temperature values. When a
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user-supplied switch between the BIN and COM terminals closes, note the following changes:
• The Main screen displays BIN in the upper-right corner of the LCD.
• The temperature setback feature is enabled and the control uses the effective On and OFF setback values (On + tSb and
OFF + tSb) to control the relay.
Note: The control displays only the original On and OFF values in both the normal and setback modes. The effective setback
On and OFF values (On + tSb and OFF + tSb) never display on the control LCD. The temperature setback adjustment
range is from -50°F to 50°F (-30°C to 30°C). Typically, heating applications require a negative temperature setback (tSb)
value, and cooling applications require a positive value.
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