Carrier 50VL-A Performance Installation Instructions Manual

Also see for Performance 50VL-A: Owner's information manual Installation instructions Installation instructions Installation instructions

Contents

36LOW TEMPERATURE COMPRESSOR LOCKOUTSWITCH—The Economizer is equipped with a low ambienttemperature lockout switch located in the outdoor airstream which isused to lock out the compressors below a 42_F (5.6_C) ambienttemperature.Economizer Control Modes—Determine the Economizer controlmode before set up of the control. Some modes of operation mayrequire different sensors. Refer to Table 10. The Economizer issupplied from the factory with a supply air temperature sensor, alow temperature compressor lockout switch, and an outdoor airtemperature sensor. This allows for operation of the Economizerwith outdoor air dry bulb changeover control. Additionalaccessories can be added to allow for different types of changeovercontrol and operation of the Economizer and unit.OUTDOOR DRY BULB CHANGEOVER— The standardcontroller is shipped from the factory configured for outdoor dry bulbchangeover control. The outdoor air and supply air temperaturesensors are included as standard.For this control mode, the outdoor temperature is compared to aselectable set point on the sensor. See Fig. 35. If the outdoor--airtemperature is above the set point, the Economizer will adjust theoutdoor air dampers to minimum position. If the outdoor--airtemperature is below the set point, the position of the outdoor--airdampers will be controlled to provide free cooling using outdoorair. When in this mode, the LED next to the free cooling set pointpotentiometer will be on. The changeover temperature set point isset using the switches on the sensor. See Fig. 35 for thecorresponding temperature changeover values.In this mode of operation, the outdoor--air temperature is comparedto the return--air temperature and the lower temperature airstream isused for cooling. When using this mode of changeover control, turnthe free cooling/enthalpy set point potentiometer fully clockwise tothe D setting. See Fig. 34 and Fig. 39.EXHAUST FANSETPOINTLED LIGHTS WHENEXHAUST CONTACTIS MADEMINIMUM DAMPERPOSITION SETTINGMAXIMUM DAMPER DEMANDCONTROL VENTILATIONSETPOINTLED LIGHTS WHENDEMAND CONTROLVENTILATION INPUTIS ABOVE SETPOINTDEMAND CONTROLVENTILATION SETPOINTLED LIGHTS WHENOUTDOOR AIR ISSUITABLE FOR FREECOOLING ENTHALPYCHANGEOVER SETPOINTA09708Fig. 34 -- Economizer Controller Potentiometer and LEDLocations(8.9°C)(11.7°C)(12.8°C)(14.4°C)(17.2°C)(20°C)(22.8°C)(25.6°C)A10134Fig. 35 -- Outdoor Air Temperature Changeover Set PointsRETURN DUCT(FIELD-PROVIDED)RETURN AIRSENSORECONOMIZERA09710Fig. 36 -- Enthalpy Sensor Mounting Location50VL-- A