Carrier Performance 48VL-A Installation Instructions Manual

Also see for 48VL-A: Owner's information manual

Contents

22Normal OperationAn LED (light--emitting diode) indicator is provided on theintegrated gas unit controller (IGC) to monitor operation. The IGCis located by removing the control access panel (see Fig. 19).During normal operation, the LED is continuously on (See Table 5for error codes).Airflow and Temperature RiseThe heating section for each size unit is designed and approved forheating operation within the temperature--rise range stamped on theunit rating plate.Table 8 shows the approved temperature rise range for each heatinginput, and the air delivery cfm at various temperature rises for agiven external static pressure. The heating operation airflow mustproduce a temperature rise that falls within the approved range.Refer to Indoor Airflow and Airflow Adjustments section to adjustheating airflow when required.Heating Sequence of Operation(See Fig. 14, 15, 16 and unit wiring label.)On a call for heating, terminal W of the thermostat is energized,starting the induced--draft motor. When the pressure switch sensesthat the induced--draft motor is moving sufficient combustion air,the burner sequence begins. This function is performed by theintegrated gas unit controller (IGC). The indoor (evaporator)--fanmotor is energized 45 sec after flame is established. When thethermostat is satisfied and W is de--energized, the burners stopfiring and the indoor (evaporator) fan motor shuts off after a45--sec time--off delay. Please note that the IGC has the capabilityto automatically reduce the indoor fan motor on delay and increasethe indoor fan motor off delay in the event of high duct staticand/or partially--clogged filter.Limit SwitchesNormally closed limit switch (LS) completes the control circuit.Should the leaving--air temperature rise above the maximumallowable temperature, the limit switch opens and the controlcircuit “breaks.” Any interruption in the control circuit instantlycloses the gas valve and stops gas flow to the burners. The blowermotor continues to run until LS resets.When the air temperature at the limit switch drops to thelow--temperature setting of the limit switch, the switch closes andcompletes the control circuit. The direct--spark ignition systemcycles and the unit returns to normal heating operation.Table 5 – LED IndicationsSTATUS CODE LED INDICATIONNormal Operation 2 OnNo Power or Hardware Failure OffLimit Switch Fault 2 FlashesFlame Sense Fault 3 FlashesFour Consecutive Limit Switch Faults 4 FlashesIgnition Lockout Fault 5 FlashesPressure Switch Fault 6 FlashesRollout Switch Fault 7 FlashesInternal Control Fault 8 FlashesTemporary 1 hr auto reset1 9 FlashesNOTES:1.This code indicates an internal processor fault that will reset itself in onehr. Fault can be caused by stray RF signals in the structure or nearby. Thisis a UL requirement.2. LED indicates acceptable operation. Do not change ignition controlboard.3. When W is energized the burners will remain on for a minimum of 60 sec.4. If more than one error code exists they will be displayed on the LED insequence.Rollout SwitchThe function of the rollout switch is to close the main gas valve inthe event of flame rollout. The switch is located above the mainburners. When the temperature at the rollout switch reaches themaximum allowable temperature, the control circuit trips, closingthe gas valve and stopping gas flow to the burners. The indoor(evaporator) fan motor (IFM) and induced draft motor continue torun until switch is reset. The IGC LED will display FAULT CODE7.Step 3 — Start--up Cooling and Make Adjust-mentsComplete 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 compressor when theoutdoor temperature is below 40°F (4.4°C) (unless accessorylow--ambient kit is installed). Do not rapid--cycle the compressor.Allow 5 minutes between on cycles to prevent compressor damage.Checking Cooling Control OperationStart and check the unit for proper cooling control operation asfollows:1. Place room thermostat SYSTEM switch in OFF position.Observe that blower motor starts when FAN switch isplaced in ON position and shuts down when FAN switch isplaced in AUTO position.2. Place SYSTEM switch in COOL position and FAN switchin AUTO position. Set cooling control below roomtemperature. Observe that compressor, condenser fan, andevaporator blower motors start. Observe that cooling cycleshuts down when control setting is satisfied. The evaporatorfan will continue to run for 90 sec.3. When using an auto--changeover room thermostat, placeboth SYSTEM and FAN switches in AUTO positions.Observe that unit operates in Heating mode whentemperature control is set to call for heating (above roomtemperature) and operates in Cooling mode whentemperature control is set to call for cooling (below roomtemperature).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 will be minimal.Checking and Adjusting Refrigerant ChargeThe refrigerant system is fully charged with PuronR (R--410A)refrigerant and is tested and factory sealed. Allow system to operatea minimum of 15 minutes before checking or adjusting charge.NOTE: Adjustment of the refrigerant charge is not required unlessthe unit is suspected of not having the proper PuronR (R--410A)charge.The charging label and the tables shown refer to systemtemperatures and pressures in cooling mode only. A refrigerantcharging label is attached to the inside of the compressor accesspanel. (See Fig. 19.) The chart includes the required liquid linetemperature at given discharge line pressures and outdoor ambienttemperatures.An accurate thermocouple-- or thermistor--type thermometer, and agauge manifold are required when using the subcooling chargingmethod for evaluating the unit charge. Do not use mercury or smalldial--type thermometers because they are not adequate for this typeof measurement.48VL-- A