Carrier 40QNB018 Installation, Start-up And Service Instructions Manual

Also see for 38BK-018: Owner's manual

Contents

COMPRESSOR FAILUREIf the System is in Cooling or Dehumidification Mode —After 5 minutes of operation, if the temperature of the in-door coil is not 4° F less than at the time the call for coolingstarted, then a compressor failure is indicated on the remotecontroller LCD display.If the System is in Heat Pump Heating Mode (38BK only)— After 5 minutes of operation, if the temperature indi-cated by the outdoor coil thermistor is not 4° F less than atthe time the call for heating started, then a compressor fail-ure is indicated.REVERSING VALVE FAILURE (38BK Only)If the System is in Cooling or Dehumidification Mode — After5 minutes of operation, if the temperature at the indoor coilis 4° F more than at the time the call for cooling started, thena reversing valve failure is indicated.If the System is in Heat Pump Heating Mode — After 5 min-utes of operation, if the temperature indicated by the out-door coil is 4° F more than at the time the call for heatingstarted, then a reversing valve failure is indicated.System Safeties and InterlocksINDOOR FAN FAILURE — If the indoor fan rpm showsgreater than 800 rpm for 30 seconds with the fan in the offmode, then this test indicates an indoor fan failure. Also, ifthe indoor fan rpm is greater than 1700 rpm for 30 seconds,then this test indicates an indoor fan failure.COMPRESSOR SHORT-CYCLING PROTECTION — Thereis a time delay of 3 minutes between compressor turning offand turning back on.INDOOR COIL FREEZE PROTECTION (Cooling or De-humidification Mode Only) — If the indoor coil tempera-ture is less than or equal to 32 F for 10 minutes after thecompressor has started, then the compressor and outdoor fanare turned off. The indoor fan continues to run at the user-selected speed until the indoor coil reaches 44 F. At that time,the compressor and outdoor fan will restart.INDOOR COIL HIGH-TEMPERATURE PROTECTION(Heat Pump Systems Only) — If indoor coil temperature isgreater than or equal to 135 F, the outdoor fan shuts down.The outdoor fan will restart automatically when the indoorcoil temperature drops to 120 F.TROUBLESHOOTINGSee Table 8 and Fig. 24 and 25 to assist in troubleshootingthe 40QN fan coil units.Table 8 — TroubleshootingPROBLEM POTENTIAL SOURCE ACTIONUnit does not operateCircuit breaker has tripped or fuse is blown Reset the circuit breaker or replace the fuse.Power failure Restart fan coil unit operation when power isrestored.Voltage is too low Confirm the available voltage.Insufficient CoolingAir filter is blocked with dust Clean the air filter.Temperature is not set properly Check and reset if necessary.Window(s) and/or door(s) are open Close window(s) and door(s).Outdoor unit is obstructed Remove the obstruction.Fan speed is too low Change the fan speedOperation mode is set to fan or auto. mode Change to cooling operation or reset temperature(using remote controller).Insufficient Heating*Air filter is blocked with dust Clean the air filter.Temperature is not set properly Check and reset if necessary.Window(s) and/or door(s) are open Close window(s) and door(s).Outdoor unit is obstructed Remove the obstruction.Unit stops during operationOff timer is operating Turn off the off timer function.Room temperature has reached the programmedset point Normal unit operation.*Heat pump systems only.15