Carrier Performance 25HPA6 Installation Instructions Manual

Also see for 25HPA6: Wiring diagram

Contents

8Time DelaysThe unit time delays include:S Five minute time delay to start cooling or heating operationwhen there is a call from the thermostat or user interface. Tobypass this feature, momentarily short and release ForcedDefrost pins.S Five minute compressor re--cycle delay on return from abrown--out condition.S Two minute time delay to return to standby operation from lastvalid communication (with Infinity only).S One minute time delay of outdoor fan at termination of coolingmode when outdoor ambient is greater than or equal to 100_F(37.78_C).S Fifteen second delay at termination of defrost before theauxiliary heat (W1) is de--energized.S Twenty second delay at termination of defrost before the outdoorfan is energized (unless fan delay defeated).S Thirty second compressor delay when quiet shift enabled.S There is no delay between staging from low to high and fromhigh to low capacity. The compressor will change from low tohigh and from high to low capacity “on the fly” to meet thedemand.Compressor Operation:The basic scroll design has been modified with the addition of aninternal unloading mechanism that opens a by--pass port in the firstcompression pocket, effectively reducing the displacement of thescroll. The opening and closing of the by--pass port is controlledby an internal electrically operated solenoid. The modulated scrolluses a single step of unloading to go from full capacity toapproximately 67% capacity.A single speed, high efficiency motor continues to run while thescroll modulates between the two capacity steps. Modulation isachieved by venting a portion of the gas in the first suction pocketback to the low side of the compressor, thereby reducing theeffective displacement of the compressor.Full capacity is achieved by blocking these vents, thus increasingthe displacement to 100%. A DC solenoid in the compressorcontrolled by a rectified 24 volt AC signal in the external solenoidplug moves the slider ring that covers and uncovers these vents.The vent covers are arranged in such a manner that the compressoroperates at approximately 67% capacity when the solenoid is notenergized and 100% capacity when the solenoid is energized. Theloading and unloading of the two step scroll is done ”on the fly”without shutting off the motor between steps.NOTE: 67% compressor capacity translates to approximately75% cooling or heating capacity at the indoor coil.The compressor will always start unloaded and stay unloaded forfive seconds even when the thermostat is calling for high stagecapacity.UTILITY RELAY *UTILITY SIGNALOPEN RELAY* SUPPLIED BY UTILITY PROVIDERMODELPLUGA06525LLSLiquid Line SolenoidMODELPLUGA06526Fig. 6 -- 2--Stage Control Board25HPA6