Carrier PrimeLINE Operation And Service Manual page 47

Code Description
Cd27 Defrost Interval (Hours or Automatic)
Cd27 controls the Defrost Timer Interval, which is the desired period of time between defrost cycles. The
user-selected intervals are 3, 6, 9, 12, 24 Hours, Off, AUTO, PuLS, AUTO2, or AUTO3. Factory default is
"AUTO". See the Defrost Operation
After a new Defrost Interval is selected, the previously selected Interval is used until the next defrost
termination, the next time the DTT contacts are OPEN, or the next time power to the control is interrupted.
If the previous value or the new value is "OFF", the newly selected value will be used immediately.
If any Auto Pre-trip sequence is initiated, Cd27 will be set to 'AUTO' unless CnF49 (OEM Reset) is set to
"Custom" AND CnF64 (Evaporator Fan Pulsing Logic) configuration variable is set to IN, in which case
Cd27 will be set to "PuLS".
CnF11 determines whether the operator will be allowed to chose "OFF" as a defrost interval option.
CnF64 determines whether the operator will be allowed to choose "PuLS" as a defrost interval option. For
units operating with "PuLS" selected, defrost interval is determined by the unit temperature setpoint and
the Evaporator Fan Pulsing Temperature Setting (Cd60). When the unit temperature setpoint is equal to
or less than the Evaporator Fan Pulsing Temperature Setting, the defrost interval is set to 6 hours.
Otherwise, the defrost interval is determined using the Automatic Defrost Interval Determination logic. In
either case, "PuLS" remains displayed in this function select code.
Cd28 Temperature Units (Degrees C or Degrees F)
Cd28 controls the temperature units (C or F) that will be shown on all temperature values. The user
selects C or F by selecting function code Cd28 and pushing the ENTER key.
The factory default value is Celsius units. This function code will display "-----" if CnF34 is set to F.
Cd29 Failure Action (Mode)
Cd29 controls the shutdown action to take if all of the control sensors are out of range (alarm code AL26)
or there is a probe circuit calibration failure (alarm code AL27).
Cd29 has one of four possible actions to select as described below:
• A - Full Cooling (Compressor is on, economized operation.)
• b - Partial Cooling (Compressor is on, standard operation.)
• C - Evaporator Fan Only (Evaporator fans on high speed, not applicable with frozen setpoints.)
• d - Full System Shutdown - Factory Default (Shut down every component in the unit.)
Cd30 In-Range Tolerance
Cd30 controls the in-range tolerance, which determines the temperature band around the setpoint which
will be designated as in-range. If the control temperature is in-range, the green IN-RANGE light will be
illuminated.
For normal temperature control, control temperature is considered in range if it is within setpoint in-range
Tolerance. There are four possible values:
• 1 = +/- 0.5°C (+/-0.9°F)
• 2 = +/- 1.0°C (+/-1.8°F)
• 3 = +/- 1.5°C (+/-2.7°F)
• 4 = +/- 2.0°C (+/-3.6°F) - Factory Default
In-range tolerance shall be set to +/- 2.0°C upon activation of Dehumidification or Bulb Mode (Cd33,
Cd35, Cd48).
When QUEST is actively controlling, in-range tolerance is not considered.
"-----" will be displayed whenever Dehumidification or Bulb Mode is enabled or when CCPC with six hour
re-activation is actively controlling.
"-----" will be displayed whenever Frozen Economy Mode is operating.
Table 4–4 Controller Function Codes
(Section 4.3.21) for information on Defrost Timer Interval.
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