Carrier Residential Air Conditioners and Heat Pumps Application Manualline

Also see for 24ANB124: Installation instructions

Carrier Residential Air Conditioners and Heat Pumps Application Manualline Manual pdf 55 page image

55TWO STAGE NON--COMMUNICATING24ACB7/25HCB6These units are a low cost 2--stage option that isnon--communicating utilizing 2 stage scroll technology. Theseunits require Performance Boost furnace (58PH, 58MEB), variablespeed furnace (58MV, 58CV) or new model variable speed fan coil(FV4C). Variable speed fan coils prior to the FV4C will NOT berated with the new Comfort series two stage units as they are notcapable of meeting the air flow requirements necessary for rating.These are designed to operate with basic 24 volt thermostat inputs.Operating AmbientThe minimum outdoor operating ambient in cooling mode is 55_F(12.78_C), and the maximum outdoor operating ambient incooling mode is 125_F (51.67_C) when operating voltage is 230v.For 208v applications, the maximum outdoor ambient is 120_F.NOTE: Units operating at high stage operation, 208v (or below)line voltage and at an outdoor ambient of 120_F (or greater), mayexperience compressor trip.NOTE: This product is not approved for low ambient cooling atthis time, and no low ambient kit is available.Airflow Selections (ECM Furnaces)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--communicating)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.