Carrier 50CR Installation Instructions Manual

Also see for Infinity 50CR Series: Owner's information manual

Contents

20Check system wiring to be sure the User Interface is powered andconnections are made A to A, B to B, etc., and wiring is not shorted.Mis--wiring or shorting of the ABCD communications wiring willnot allow successful communications. Correcting wiring faults willclear the code and re--establish communications.Shorting or mis--wiring the low voltage system wiring will not causedamage to unit control or to User Interface but may cause the lowvoltage fuse to open.STATUS CODE 46, BROWNOUT CONDITIONIf the secondary voltage of the transformer falls below 15--vac fora period exceeding 4 seconds, Status Code 46 will be displayed onSTATUS LED and the User Interface will command the controlboard to turn off Y output controlling compressor.When secondary voltage rises above 17--vac for more than 4seconds, the brownout condition is cleared and normal systemoperation will resume subject to any minimum compressoroff--delay function which may be in effect. Brownout does not affectblower or electric heater operation.STATUS CODE 53, OUTDOOR AIR TEMPERATURE SENSORFAULTIf an OAT sensor is found at power--up, input is constantly checkedto be within a valid temperature range. If sensor is found to be openor shorted at any time after initial validation, Status Code 53 will bedisplayed at amber STATUS LED.Check for faults in wiring connecting sensor to OAT terminals.Using an Ohm meter, check resistance of thermistor for a short oropen condition.If thermistor is shorted or open, replace it to return the system tonormal operation. If fault is in the wiring connections, correcting thefault will clear the code and return the system to normal operation.NOTE: If fault condition is an open thermistor or a wiring problemthat appears to be an open thermistor and the power to the unit iscycled off, the fault code will be cleared on the next power--up butthe fault will remain and system operation will not be as expected.This is because on power--up, the unit control cannot discern thedifference between an open sensor or if a sensor is not installed.Step 2—Sequence of OperationThe packaged heat pump is designed for installation with acommunicating User Interface. This unit will not respond tocommands provided by a common thermostat except under certainemergency situations described in Step 1—Start--Up.The User Interface uses temperature, humidity and other datasupplied from indoor and outdoor system components to controlheating or cooling system for optimum comfort. The unit will becommanded by User Interface to supply airflow. The unit willoperate the indoor blower at requested airflow for most modes.The nominal requested airflow will be 350 cfm per ton of nominalcooling capacity as defined by unit size. Actual airflow request willbe adjusted from nominal using indoor and outdoor temperatureand indoor humidity data to optimize the system operation foroccupant comfort and system efficiency. Refer to User Interfaceliterature for further system control details.Airflow during electric heater operation must be greater than aminimum level for safe operation. If User Interface instructs unit toturn on electric heat and the requested airflow is less than theminimum level the unit control will override requested value.NOTE: Once the compressor has started and then has stopped, itshould not be started again until 4 minutes have elapsed. Thecooling cycle remains “on” until the room temperature drops topoint that is slightly below the cooling control setting of the userinterface. Additionally, there is a 5--minute compressor delay builtinto the control for heat pump heating mode.Step 3—Check for Refrigerant LeaksLocate and repair refrigerant leaks and charge the unit as follows:1. Use both high-- and low--pressure ports to relieve systempressure and reclaim remaining refrigerant.2. Repair leak following accepted practices.NOTE: Install a bi--flow filter drier whenever the system has beenopened for repair.3. Check system for leaks using an approved method.4. Evacuate refrigerant system and reclaim refrigerant if noadditional leaks are found.5. Charge unit with Puron (R--410A) refrigerant, using avolumetric--charging cylinder or accurate scale. Refer to unitrating plate for required charge.Step 4—Start--Up AdjustmentsComplete the required procedures given in the Pre--Start--Upsection before starting the unit. Do not jumper any safety deviceswhen operating the unit. Do not operate the unit in cooling modewhen the outdoor temperature is below 40°F (unless accessorylow--ambient kit is installed). Do not rapid cycle the compressor.Allow 5 min. between “on” cycles to prevent compressor damage.CHECKING COOLING AND HEATING CONTROLOPERATIONStart and check the unit for proper control operation as follows:1. Place room UI SYSTEM switch or MODE control in OFFposition. Observe that blower motor starts when FAN modeis placed in FAN ON position and shuts down within 60 sec(030--060 size) or 30 sec (024 size) when FAN MODEswitch is placed in AUTO position.2. Place system switch or MODE control in HEAT position. Setcontrol above room temperature. Observe that compressor,outdoor fan, and indoor blower motors start. Observe thatheating cycle shuts down when control setting is satisfied.3. When using an automatic changeover room thermostat,place both SYSTEM or MODE control and FAN modeswitches in AUTO positions. Observe that unit operates incooling mode when temperature control is set to “call forcooling” (below room temperature), and unit operates inheating mode when temperature control is set to “call forheating” (above room temperature).IMPORTANT: Three--phase, scroll compressors are directionoriented. Unit must be checked to ensure proper compressor3--phase power lead orientation. If not corrected within 5 minutes,the internal protector will shut off the compressor. The 3--phasepower leads to the unit must be reversed to correct rotation. Whenturning backwards, the difference between compressor suction anddischarge pressures may be dramatically lower than normal.50CR