Carrier 24VNA6 Series, Installation Instructions Manual

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24VNA6: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
11
Step 12 – Pumpdown & Evacuation
Because this system has an inverter controlled compressor the
conventional procedure cannot be used to "pump down" and isolate the
refrigerant into the outdoor unit. The UI (User Interface) has provisions
to assist in performing this function. Pump Down
1. Connect gages to liquid and vapor or suction capillary service ports
to monitor operating pressures during and at completion of the
procedure.
2. In the "installation and service" menu of the UI (see Fig. 11 ), go to
"refrigerant charging" and then "pump down" (see Fig. 11 &
Fig. 12 ).
3. Pump down in COOL mode allows refrigerant to be isolated in
outdoor unit. Set desired time period. Default time period for the
procedure is 120 minutes. See Fig. 22 .
4. Select Start on UI to begin the pumpdown process. Unit will begin
running in selected mode after a brief delay and a status screen will
be displayed. See Fig. 23 .
5. Close the liquid service valve.
6. The unit will run with the low pressure protection set to indicate
pumpdown is complete when the suction pressure drops below 20
psig. Compressor protections are still active to prevent damage to
the compressor or inverter (high pressure, high current, etc.).
7. Once system indicates pumpdown complete or failure to complete
shutdown, close vapor service valve.
8. A recovery system will be required to remove final quantity of
refrigerant from indoor coil and line set.
9. Remove power from indoor and outdoor unit prior to servicing unit.
A200040
Fig. 22 – Pump Down Setup Screen
A200041
Fig. 23 – Pump Down Status Screen
Evacuation and Recovery of Refrigerant from within
24VNA6
Because the 5 ton unit has an EXV for the vapor injection device,
additional steps must be taken to open the EXV if the OD unit must be
evacuated for service reasons. If the EXV is not open when pulling a
vacuum or recovering refrigerant from the OD unit, extended evacuation
time may be required and/or inadequate vacuum obtained. The UI (User
Interface) has provisions to open the EXV for refrigerant recovery
and/or evacuation.
1. Connect gages to liquid and vapor or suction capillary service ports
to monitor operating pressures during and at completion of the
procedure. Attach recovery system or vacuum pump to gage set as
needed for the service procedure. The service valves must be open
to evacuate the unit through the line set service ports. The suction
capillary service port is a direct connection to the suction port of the
compressor.
2. In the "installation and service" menu of the UI (see Fig. 11 ), go to
"refrigerant charging" and then "evacuation" (see Fig. 12 ) and
Fig. 13 ).
3. Set desired time period. Default time period for the procedure is
120 minutes. See Fig. 24 .
4. Select START on UI to open the valve.
5. Begin evacuation or refrigerant recovery as required for the
procedure after UI indicates the EXV is open. Power may be
removed from outdoor unit after the UI indicates "READY TO
EVACUATE." See Fig. 25 .
6. Remove power from indoor and outdoor unit prior to servicing unit.
The EXV will retain the open position.
NOTE: See service training materials for troubleshooting the EXV
using EXV CHECK mode.
A200042
Fig. 24 – Evacuation Setup Screen
A200043
Fig. 25 – Evacuation Status Screen