Carrier 48EZ(N)-A Installation Instructions Manual

Also see for 48EZ(N) - A: Installation instructions

Contents

182. Remove the current speed tap wire from the “LOW”terminal on the interface fan board (IFB) (See Fig. 13) andplace vinyl cap over the connector on the wire.3. Connect the desired speed tap wire to the “LOW” terminalon the interface fan board (IFB).Two Cooling Fan Speeds Set-up (Dehumidificationfeature used)IMPORTANT: Dehumidification control must open controlcircuit on humidity rise above set point.Use of the dehumidification cooling fan speed requires use ofeither a 24 VAC dehumidistat or a thermostat which includescontrol of a 24 VAC dehumidistat connection. In either case, thedehumidification control must open the control circuit on humidityrise above the dehumidification set point.1. Remove fan speed tap wire from the “LOW” terminal onthe interface fan board (IFB) (See Fig. 13).2. Determine correct normal cooling fan speed for unit andapplication. Add the wet coil pressure drop in Table 9 tothe system static to determine the correct cooling airflowspeed in Table 7 that will deliver the nominal coolingairflow as listed in Table 1 for each size.3. Remove the vinyl cap off of the desired speed tap wire(Refer to Table 6 for color coding) for the normal coolingfan speed and place desired speed tap wire on “HIGH” onthe interface board.4. Refer to airflow tables (Table 7) to determine allowablespeeds for the dehumidification cooling fan speed. In Table7, speeds that are not allowed for dehumidification coolingare shaded.5. Remove the vinyl cap off of the desired speed tap wire(Refer to Table 6 for color coding) for the dehumidificationcooling fan speed and place desired speed tap wire on the“LOW” connection on the interface board (IFB). Verifythat static pressure is in the acceptable range for the speedtap to be used for dehumidification cooling.6. Use any spare vinyl plugs to cap any unused speed tapwires.Continuous Fan OperationWhen the DEHUM feature is not used, the continuous fan speedwill be the same as cooling fan speed. When the DEHUM featureis used, the continuous fan will operate on IFB “LOW” speedwhen the DH control lead is not energized, or IFB “HIGH” speedwhen the DH lead is energized (see Fig. 13).NOTE: For heat pump operation, the recommended airflow is 350to 450 CFM for each 12,000 Btuh of rated cooling capacity.Table 6 – Color Coding for Indoor Fan Motor LeadsBlack = High SpeedOrange = Med---High SpeedRed = Med SpeedPink = Med---Low SpeedBlue = Low SpeedCOMLOWHIGHGASHEATQ1R1LC8RL3Q3DCR QCRQC1G1G2A7D4D6C2OILLR9 AB A15C4C9C0R4 RL4C7R2 R3 R5 R6QCBY Y R U C 24VACJW1P2P1W2 Y2/ Y1/YDH G C RSSTZ-8P3 SDL24VAC/R CDM/CF1QC6 QC7 QC4 QC3K2 K1D2RI0RI2JM6RI DLJM5U1C3D3D5JW3JW2JW4JW73 AMPCA09058Fig. 13 -- Interface Fan Board (IFB)48EZ -- A