Carrier PY5G B Series Installation Instructions Manual

PY5G--B: Installation InstructionsManufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.26Normal OperationAn LED (light-emitting diode) indicator is provided on the integratedgas unit controller (IGC) to monitor operation. The IGC is located byremoving the control access panel (see Fig. 25). During normaloperation, the LED is continuously on (See Table 8 for 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 the unitrating plate.Table 11 show the approved temperature rise range for each heatinginput, and the air delivery CFM at various temperature rises for a givenexternal static pressure. The heating operation airflow must produce atemperature rise that falls within the approved range. For single phaseunits only, “High” blower speed is for high static cooling only and mustnot be used for gas heating speed.Refer to Indoor Airflow and Airflow Adjustments section to adjustheating airflow when required.Heating Sequence of Operation(See Fig. 17, Fig. 18 and unit wiring label)On a call for heating, terminal W of the thermostat is energized, startingthe induced-draft motor for a 5 second pre-purge. When the pressureswitch senses that the induced-draft motor is moving sufficientcombustion air, the burner sequence begins. This function is controlledby the integrated gas unit controller (IGC). The indoor (evaporator) –fanmotor is energized 30 seconds after flame is established. When thethermostat is satisfied and W is de-energized, the burners stop firing andthe indoor (evaporator) fan motor shuts off after a 90 second time-offdelay. Please note that the IGC has the capability to automatically reducethe indoor fan motor on delay and increase the indoor fan motor offdelay in the event of high duct static and/or a partially-clogged filter.Limit SwitchesNormally closed limit switch (LS) completes the control circuit. Shouldthe leaving-air temperature rise above the maximum allowabletemperature, the limit switch opens and the control circuit “breaks.” Anyinterruption in the control circuit instantly closes the gas valve and stopsgas flow to the burners. The blower motor continues to run until LSresets.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 system cyclesand the unit returns to normal heating operation.Rollout SwitchThe function of the rollout switch is to close the main gas valve in theevent of flame rollout. The switch is located above the main burners.When the temperature at the rollout switch reaches the maximumallowable temperature, the control circuit trips, closing the gas valve andstopping gas flow to the burners. The indoor (evaporator) fan motor(IFM) and induced draft motor continue to run until switch is reset. TheIGC LED will display FAULT CODE 7.Step 3 – Start-up Cooling and Make AdjustmentsComplete the required procedures given in the Pre-Start-Up sectionbefore starting the unit. Do not jumper any safety devices whenoperating the unit. Do not operate the compressor when the outdoortemperature is below 40°F (4.4°C) (unless accessory low-ambient kit isinstalled). Do not rapid-cycle the compressor. Allow 5 minutes betweenon cycles to prevent compressor damage.Checking Cooling Control OperationStart and check the unit for proper cooling control operation as follows:1. Place room thermostat SYSTEM switch in OFF position. Observethat blower motor starts when FAN switch is placed in ON positionand shuts down when FAN switch is placed in AUTO position.2. Place SYSTEM switch in COOL position and FAN switch inAUTO position. Set cooling control below room temperature.Observe that compressor, condenser fan, and evaporator blowermotors start. Observe that cooling cycle shuts down when controlsetting is satisfied. The evaporator fan will continue to run for 90sec.3. When using an auto-changeover room thermostat, place bothSYSTEM and FAN switches in AUTO positions. Observe that unitoperates in Heating mode when temperature control is set to call forheating (above room temperature) and operates in Cooling modewhen temperature control is set to call for cooling (below roomtemperature).IMPORTANT: Three-phase, scroll compressors are direction oriented.Unit must be checked to ensure proper compressor 3-phase power leadorientation. If not corrected within 5 minutes, the internal protector willshut off the compressor. The 3-phase power leads to the unit must bereversed to correct rotation. When turning backwards, the differencebetween compressor suction and discharge pressures will be minimal.Checking and Adjusting Refrigerant ChargeThe refrigerant system is fully charged with R-454B refrigerant and istested and factory sealed. Allow system to operate a minimum of 15minutes before checking or adjusting charge.NOTE: Adjustment of the refrigerant charge is not required unless theunit is suspected of not having the proper R-454Bcharge. If adjustingcharge, an R-454B leak detector must be actively monitoring during theprocess.NOTE: Some units have fixed orifice refrigerant metering devices.There is a different charging procedure for both expansion devices.Refer to the correct procedure for your unit.Table 8 – LED IndicationsSTATUS CODE LED INDICATIONNormal Operation**. LED indicates acceptable operation. Do not change ignition control board.OnNo Power or Hardware Failure OffCheck fuse, low voltage circuit 1 FlashLimit 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 reset ††. This code indicates an internal processor fault that will reset itself in one hr.Fault can be caused by stray RF signals in the structure or nearby. This is aUL requirement.NOTES:1. When W is energized the burners will remain on for a minimum of 60 sec.2. If more than one error code exists they will be displayed on the LED insequence.9 FlashesWARNING! EXPLOSION HAZARDFailure to follow this warning could result indeath, serious personal injury, and/or propertydamage.Never use air or gases containing oxygen forleak testing or operating refrigerantcompressors. Pressurized mixtures of air orgases containing oxygen can lead to anexplosion.