Carrier 50PD05 Operating And Service Instructions

Also see for 48PD05: User manual User's information manual Installation instructions

Sensor TrimCorrective offsets can be applied to the space temperature and thesupply air temperature sensor readings. These corrections are set inthe Configuration--,TRIM menu for the display, or in theMaintenance--,TRIM table for CCN. See the Indoor Air Qualitysection for available adjustments to IAQ and OAQ sensor readings.The space temperature may be corrected by entering either acalibration temperature value in SPT.C, or an offset temperaturevalue in SPT.T. The supply-air temperature may be corrected byentering either a calibration temperature value in SAT.C, or anoffset temperature value in SAT.T. The return-air temperature maybe corrected by entering either a calibration temperature value inRAT.C or an offset temperature value in RAT.T. Temperaturecorrections should only be made if sensor readings are compared toan accurate reference temperature measurement device.Transducer TroubleshootingThe electronic control uses suction pressure transducers to measurethe suction pressure of the refrigerant circuits. The pressure/voltagecharacteristics of these transducers are in shown in Table 18, the5vdc power is applied to legs A and B of the transducer and legs Bto C represent the voltage drop shown in the table. The accuracy ofthese transducers can be verified by connecting an accuratepressure gauge to the second refrigerant port in the suction line.Forcing Inputs and OutputsMany variables may have their value forced through CCN ordirectly at the local display. This can be useful during diagnostictesting and also during operation, typically as part of an advancedthird party control scheme. Input and output points that may beforced are indicated as 'forcible' in the write status column of thedisplay and CCN tables.If the user needs to force a variable, follow the same process aswhen editing a configuration parameter. A forced variable will bedisplayed on the Scrolling Marquee with a blinking period "."following its value. A forced value on Navigator TM accessory isindicated with a blinking "f'. A forced value on CCN devices isindicated with "Control" if forced at the unit display, or"Supervisor" if forced via CCN. To remove a local force with theScrolling Marquee, select the point with the ENTER key and thenpress the up-arrow and down-arrow keys simultaneously.IMPORTANT: In the case of a control power reset, any force ineffect at the time of power reset will be cleared.38