Carrier Infinity 25VNA4 Installation Instructions Manual

Also see for Infinity 25VNA4: Service manual Owner's manual

25VNA4: Installation InstructionsManufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.11Step 13 – Pumpdown & EvacuationBecause this system has an inverter controlled compressor and EXV theconventional procedure cannot be used to "pump down" and isolate therefrigerant into the outdoor unit. The UI (User Interface) has provisionsto assist in performing this function. Pump Down1. Connect gages to liquid and vapor or suction capillary service portsto monitor operating pressures during and at completion of theprocedure.2. In the "installation and service" menu of the UI (see Fig. 11), go to"refrigerant charging" and then "pump down" (see Figs. 11 & 12).3. Select mode to pump down in (COOL or HEAT), COOL modeallows refrigerant to be isolated in outdoor unit. HEAT modeallows the refrigerant to be isolated in indoor coil and lineset. Setdesired time period. Default time period for the procedure is 120minutes. See Fig. 22.4. Select Start on UI to begin the pumpdown process. Unit will beginrunning in selected mode after a brief delay and a status screen willbe displayed. See Fig. 23.5. Close the liquid service valve.6. The unit will run in selected mode with the low pressure protectionset to indicate pumpdown is complete when the suction pressuredrops below 20 psig. Compressor protections are still active toprevent damage to the compressor or inverter (high pressure, highcurrent, etc.).7. Once system indicates pumpdown complete or failure to completeshutdown, close vapor service valve.8. A recovery system will be required to remove final quantity ofrefrigerant from indoor coil and line set.9. Remove power from indoor and heat pump unit prior to servicingunit.NOTE: A small quantity of charge remains in the OD unit that must bemanually recovered if isolating refrigerant to indoor coil and lineset viaHEAT mode PUMP DOWN.A20040Fig. 22 – Pump Down Setup ScreenA20041Fig. 23 – Pump Down Status ScreenEvacuation and Recovery of Refrigerant from within25VNABecause this system has an EXV for the heating expansion device,additional steps must be taken to open the EXV if the heat pump unitmust be evacuated for service reasons. If the EXV is not open whenpulling a vacuum or recovering refrigerant from the heat pump unit,extended evacuation time may be required and/or inadequate vacuumobtained. The UI (User Interface) has provisions to open the EXV forrefrigerant recovery and/or evacuation.1. Connect gages to liquid and vapor or suction capillary service portsto monitor operating pressures during and at completion of theprocedure. Attach recovery system or vacuum pump to gage set asneeded for the service procedure. The service valves must be opento evacuate the unit through the line set service ports. The suctioncapillary service port is a direct connection to the suction port of thecompressor.2. In the "installation and service" menu of the UI (see Fig. 11), go to"refrigerant charging" and then "evacuation" (see Fig. 12) andFig. 13).3. Set desired time period. Default time period for the procedure is120 minutes. See Fig. 24.4. Select START on UI to open the valve.5. Begin evacuation or refrigerant recovery as required for theprocedure after UI indicates the EXV is open. Power may beremoved from heat pump after the UI indicates "READY TOEVACUATE." See Fig. 25.6. Remove power from indoor and heat pump unit prior to servicingunit. The EXV will retain the open position.NOTE: See service training materials for troubleshooting the EXVusing EXV CHECK mode.A20042Fig. 24 – Evacuation Setup ScreenA20043Fig. 25 – Evacuation Status Screen