4signifies a hazard which could result in personal injury or death. CAUTION isused to identify unsafe practices which may result in minor personal injury orproduct and property damage. NOTE is used to highlight suggestions which willresult in enhanced installation, reliability, or operation.INTRODUCTIONCarrier’s PTAC Comfortt Series non--programmable thermostat is awall--mounted, low--voltage thermostat which maintains room temperature bycontrolling the operation of a heating and/or air conditioning system. Both heatpump and air conditioner models are available. A variety of features are providedincluding battery operation, memory in case of power interruption, separateheating and cooling setpoints, backlighting, and built--in installer test.This Installation Instruction guide and owners manual covers installation,configuration, start up and operation of the PTAC specific Comfort Series line ofthermostats.INSTALLATION CONSIDERATIONSModelsThere are two models for the PTAC Comfort Series non--programmable thermostat,AC and HP versions. The model PTACSTAT--NP--HC--x is designed for ACsystems, controlling one stage of cooling and one stage of heating. It will not operatea heat pump. Model PTACSTAT--NP--HP--x is designed for HP systems, controllingone stage of cooling and two stages of heating. The HP thermostat model can beconverted to an AC unit. Select the appropriate model for the intended application.PowerAll Comfort Series models are dual powered. They can operate from batteries(optional) or 24VAC power. Operation from 24VAC is preferred, if available.