Carrier 24APA7 Performance Installation Instructions Manual

Also see for 24APA7 Performance: Product data Wiring diagram

Contents

5Airflow Selections (ECM Furnaces -- non commu-nicating)The ECM Furnaces provide blower operation to match thecapacities of the compressor during high and low stage coolingoperation. Tap selections on the furnace control board enable theinstalling technician to select the proper airflows for each stage ofcooling. Below is a brief summary of the furnace airflowconfigurations1. The Y2 call for high stage cooling energizes the “Cool” tapon the control board. The grey wire from cool tap is connec-ted to tap 5 on the motor. Refer to the furnace Product Datato find the corresponding airflow. If the airflow setting forhigh cooling needs to be switched from tap 5 to a differenttap, jumper a connection from the cool tap to the desired tapso that the Y2 signal is communicated via the cool tap to thedesired speed tap.2. The Y1 call for low stage cooling energizes the “Fan” tapon the control board. The red wire from the fan tap is con-nected to tap 1 on the motor. Refer to the furnace ProductData to find the corresponding airflow. If the airflow settingfor low cooling needs to be switched from tap 1 to a differ-ent tap, jumper a connection from the Fan tap to the desiredtap so that the Y1 signal is communicated via the Fan tap tothe desired speed tap. The Y1 setting will also govern thecontinuous fan airflow for the furnace.Refer to the literature for the furnace for further details.Airflow Selection for Variable Speed Furnaces(non--communicating)The variable speed furnaces provide blower operation to match thecapacities of the compressor during high and low stage coolingoperation. The furnace control board allows the installingtechnician to select the proper airflows for each stage of cooling.Below is a summary of required adjustments. See furnaceinstallation instructions for more details:1. Turn SW1----5 ON for 400 CFM/ton airflow or OFF for 350CFM/ton airflow. Factory default is OFF.2. The A/C DIP switch setting determines airflow during highstage cooling operation. Select the A/C DIP switch settingcorresponding to the available airflow shown in the furnaceInstallation Instructions that most closely matches the re-quired airflow shown in the air conditioning Product Datafor HIGH speed.3. The CF DIP switch setting determines airflow during lowstage cooling operation. Select the CF DIP switch settingcorresponding to the available airflow shown in the furnaceinstallation instructions that most closely matches the re-quired airflow shown in the air conditioning Product Datafor LOW speed. If a higher or lower continuous fan speed isdesired, the continuous fan speed can be changed using thefan switch on the thermostat. Refer to the furnace Installa-tion Instructions for details of how to use this feature.Airflow Selection for FV4C Fan Coils (non--com-municating)The FV4 provides high-- and low--stage blower operation to matchthe capacities of the compressor at high-- and low--stage.To select recommended airflow, refer to the FV4C InstallationInstructions. The FV4C utilizes an Easy Select control board thatallows the installing technician to select proper airflows. This fancoil has an adjustable blower--off delay factory set at 90 sec. forhigh-- and low--stage blower operation.When using a communicating control with the fan coil or thefurnace, dip--switch adjustments are not necessary. The outdoorunit configuration and the indoor airflows are determined bycommunicating control setup.Start--UpCAUTION!UNIT OPERATION AND SAFETY HAZARDFailure to follow this caution may result in personal injury,equipment damage or improper operation.S Do not overcharge system with refrigerant.S Do not operate unit in a vacuum or at negative pressure.S Compressor dome temperatures may be hot.CAUTION!PERSONAL INJURY HAZARDFailure to follow this caution may result in personal injury.Wear safety glasses, protective clothing, and gloves whenhandling refrigerant and observe the following:S Front seating service valves are equipped with Schradervalves.SYSTEM FUNCTIONS AND SEQUENCEOF OPERATIONThe 24APA7 models utilize either an Infinity Communicating UserInterface or a 2-stage cooling indoor thermostat. With a call forfirst stage cooling, the outdoor fan and low-stage compressor areenergized. If low-stage cannot satisfy cooling demand, high-stageis energized by the second stage of indoor thermostat. After secondstage is satisfied, the unit returns to low-stage operation until firststage is satisfied or until second stage is required again.When both first stage and second stage cooling are satisfied, thecompressor will shut off. When a 2-stage unit is operating atlow-stage, system vapor (suction) pressure will be higher than astandard single-stage system or high-stage operation.When the outdoor ambient is more than 100_F (37.8_C), theoutdoor fan will continue to run for one minute after compressorshuts off. this reduces pressure differential for easier starting in thenext cycle.24APA7