Outdoor Unit Refrigerant Recovery Method; Refrigerant Recovery From Failed Outdoor Unit (Pump-Down); Note For Refrigerant Recovery Operation; Refrigerant Recovery Procedure A (Case Of No Outdoor Unit Backup Operation Setting) - Toshiba MMY-MAP0804FT8(ZG)-E Service Manual

10. OUTDOOR UNIT REFRIGERANT RECOVERY METHOD

10-1. Refrigerant Recovery from Failed Outdoor Unit (Pump-Down)

This product supports refrigerant pump-down, a function which allows refrigerant to be recovered from an
outdoor unit in need of repair using a normal outdoor unit in a system featuring multiple outdoor units.

10-1-1. Note for refrigerant recovery operation

When performing pump-down operation, take note of the following matters:
Note 1: The pump-down refrigerant recovery rate changes with outside temperature and other factors.
After pump-down is completed, recover any residual gas using a refrigerant recovery device, etc., and
be sure to measure the amount of recovered refrigerant. (The refrigerant recovery rate can be
improved by heating the accumulator of the outdoor unit to be repaired during pump-down operation.)
Note 2: If pump-down has been performed, the system cannot be operated until the faulty outdoor unit is
repaired.
(Continued operation would be impossible due to a refrigerant overcharge.)
Note 3: If outdoor PMVs 1 and 2 both happen to be faulty (unable to open) or PMV 4 fails while fully closed,
the refrigerant in the heat exchangers (or sub-heat exchangers) cannot be recovered. In that case,
recover any residual gas in the heat exchangers (or sub-heat exchangers) using a tube piercing valve
or some other tool. After a pump-down operation, do not perform any welding until the residual gas in
the heat exchangers is recovered.

10-1-2. Refrigerant recovery procedure A (Case of no outdoor unit backup operation setting)

<Work procedure>
Turn on the power supply to the system at the source, but leave the system switched off.
If the fault involves poor insulation of a compressor motor, remove the motor leads before the power is turned on.
[Setup of failed outdoor unit]
(1) Connect the check joint of liquid pipe and the low pressure-side check joint using a charge hose, and purge
the hose of air (to recover refrigerant from the liquid tank and heat exchangers).
(2) Fully close the liquid pipe service valve and service valve at discharge gas side of the failed outdoor unit.
(Leave the service valves of the suction gas and balance pipes fully open.)
(3) If the oil is likely to has degraded due to a compressor fault, disconnect the SV3A valve connector of the
failed outdoor unit (to prevent the degraded oil from flowing into other outdoor units).
(4) Set SW01/02/03 on the interface P.C. board of the failed outdoor unit to 2/11/1. After [rd] [... ... ...] is
displayed on the 7-segment display, push SW04 and hold for 5 seconds or more.
(5) [rd] [... FF] will be displayed on the 7-segment display, and pump-down operation will start.
* To put the operation on hold midway, turn off the power supply to all the outdoor units, or push SW05 on the
interface P.C. board.
(3)
If oil has degraded due to
compressor fault, undo SV3A
valve connector.
(4) Set SW01/02/03 to 2/11/1.
(5) [rd] [ FF] is displayed (pump-down operation starts).
Behavior during pump-down operation
AMP Air Conditioning
Header unit
[rd] [ ... ... ...] is displayed.
↓
Push SW04 and hold for 5 seconds or more.
Outdoor unit Behavior
Compressors: Turned off
Outdoor fan: On
PMV1, PMV2 and PMV4: Open
Failed outdoor unit
SV2/3A/3B/3C/3D/3E/3F: On
SV41/42/43/5/6: On
Operates in test cooling
Every other outdoor unit
operation mode
Interface P.C. board of failed outdoor unit
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(1)
Connect liquid pipe check joint and low
pressure-side check joint using charge
hose, and purge hose of air.
(2)
Fully close liquid pipe service valve and
valve at discharge gas side.
(Leave service valves of gas and
balance pipes fully open.)