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.27The charging label and the tables shown refer to system temperaturesand pressures in cooling mode only. A refrigerant charging label isattached to the inside of the compressor access panel. (See Table 10Subcool chart for units with TXV and superheat chart for units withfixed orifice.) The chart includes the required liquid line temperature atgiven discharge line pressures and outdoor ambient temperatures.A superheat chart is attached to the inside of the compressor access panelfor the unit with fixed metering device. Refer to the charging procedureon the label.An accurate thermocouple- or thermistor-type thermometer, and a gaugemanifold are required when using the subcooling charging method forevaluating the unit charge. Do not use mercury or small dial-typethermometers because they are not adequate for this type ofmeasurement.Proceed as follows:1. Remove caps from low- and high-pressure service fittings.2. Using hoses with valve core depressors, attach low- andhigh-pressure gauge hoses to low- and high-pressure servicefittings, respectively.3. Start unit in Cooling Mode and let unit run until system pressuresstabilize.4. Measure and record the following:a. Outdoor ambient-air temperature (°F [°C] db).b. Liquid line temperature (°F [°C]).c. Discharge (high-side) pressure (psig).d. Suction (low-side) pressure (psig) (for reference only).5. Using “Cooling Charging Charts,” compare outdoor-airtemperature (°F [°C] db) with the discharge line pressure (psig) todetermine desired system operating liquid line temperature (SeeTable 10).6. Compare actual liquid line temperature with desired liquid linetemperature. Using a tolerance of ± 2°F (±1.1°C), add refrigerant ifactual temperature is more than 2°F (1.1°C) higher than properliquid line temperature, or remove refrigerant if actual temperatureis more than 2°F (1.1°C) lower than required liquid linetemperature.NOTE: If the problem causing the inaccurate readings is a refrigerantleak, refer to the Check for Refrigerant Leaks section.Indoor Airflow and Airflow AdjustmentsNOTE: Be sure that all supply-and return-air grilles are open, free fromobstructions, and adjusted properly.This unit has independent fan speeds for gas heating and cooling modes.Single phase models also have a dedicated continuous fan speed. Allmodels (1 phase and 3 phase), have a field-selectable capability to runtwo different cooling speeds: A normal cooling fan speed (350-450CFM/Ton) and an enhanced dehumidification fan speed (As low as 320CFM/Ton) for use with either a dehumidistat or a thermostat thatsupports dehumidification.This unit is factory-set for use with a single cooling fan speed. For singlephase models, the cooling speed is marked “COOL” on the IGC (SeeFig. 23). For 3-phase models, the cooling speed is marked “LOW” onthe interface board (IFB) (See Fig. 23). The factory-shipped settings arenoted in Table 11. There are up to 3 additional speed tap wires availablefor use in either gas heating mode, cooling mode, or continuous fanmode (For color coding on the indoor fan motor leads, see Table 9). Forsingle phase models, one of the additional speed tap wires is connectedto the continuous fan, with the other 2 wires shipped loose in the controlbox near the IGC. For three phase models, the additional 3 speed tapwires are shipped loose with vinyl caps and are located in the control boxnear the interface fan board (IFB) (See Fig. 23).Gas Heating Fan Speed Set-up:To change the gas heating speed:1. Remove existing speed tap wire from the “HEAT” terminal on theIGC.2. Connect the desired speed tap wire on the “HEAT” terminal on theIGC board. Make sure that the speed chosen delivers temperaturerise within the rise range listed on the unit. “High” speed is for highstatic cooling only, and must not be used for gas heating. “High”blower speed is for high static cooling only and must not be usedfor gas heating speed.Cooling Fan Speed Set-up (Dehumidificationfeature not used):To change cooling speed:1. Remove existing speed tap wire from the “COOL” terminal on theIGC board. Add the wet coil pressure drop in Table 12 to the systemstatic to determine the correct cooling airflow speed in Table 9 thatwill deliver the nominal cooling airflow listed in Table 1 for eachsize.2. Connect the desired speed tap wire on the “COOL” terminal on theIGC board.Dehumidification Cooling Fan Speed Set-up :IMPORTANT: Dehumidification control must open control circuit onhumidity rise above set point.Use of the dehumidification cooling fan speed requires use of either a 24VAC dehumidistat or a thermostat which includes control of a 24 VACdehumidistat connection. In either case, the dehumidification controlmust open the control circuit on humidity rise above thedehumidification set point.1. Move shunt jumper on IGC board to “DH” (See Fig. 23).2. Refer to airflow table (Table 11) to determine allowable speeds forthe dehumidification cooling fan speed. Speeds that are not allowedare shaded in Table 11.3. Connect selected speed tap wire to “DHUM” terminal on the IGCboard. Verify that static pressure is in the acceptable range for thespeed tap to be used for dehumidification cooling.CAUTION!UNIT DAMAGE HAZARDFailure to follow this caution may result in unit damage.When evaluating the refrigerant charge, an indicated adjustment to thespecified factory charge must always be very minimal. If a substantialadjustment is indicated, an abnormal condition exists somewhere in thecooling system, such as insufficient airflow across either coil or bothcoils.CAUTION!UNIT OPERATION HAZARDFailure to follow this caution may result in unit damage.For cooling operation, the recommended airflow is 350 to 450 cfm foreach 12,000 Btuh of rated cooling capacity. For heating operation, theairflow must produce a temperature rise that falls within the rangestamped on the unit rating plate.WARNING!ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injury or death.Disconnect electrical power to the unit and install lockout tag beforechanging blower speed.