Carrier 42NQV025H Service Manual

Contents

– 43 –Item12. PulseModulatingvalve (P.M.V.)Operation flow and applicable data, etc.This function controls throttle amount of therefrigerant in the refrigerating cycle.According to operating status of the air conditioner,this function also controls the open degree of valvewith an expansion valve with pulse Modulation.Description1) When starting the operation, move thevalve once until it fits to the stopper.(Initialize)* In this time, “Click” sound may beheard.2) Adjust the open degree of valve by superheat amount. (SH control)3) If the discharge temperature was exces-sively up, adjust the open degree of valveso that it is in the range of set tempera-ture.(Discharge temp. control)4) When defrost operation is performed, theopen degree of valve is adjusted accord-ing to each setup conditions duringpreparation for defrost and during defrostoperation (4-way valve is inversed.).5) To turn off the compressor while the airconditioner stops by control of thethermostat or by remote controller, adjustthe open degree of valve to the setupvalue before stop of the compressor.* SH (Super Heat amount) =Ts (Temperature of suction pipe of the compressor) –Tc or Te (Heat exchanger temperature at evaporation side)* PMV: Pulse Modulating ValveStarting upDefrostInitializeMove toinitial positionPMV open degree controlSH control Tdrelease controlStop byremote controllerPower OFFRoom temp. sensor(Ta sensor) controlCompressor ONcontrolFILE NO. SVM-07013