Toshiba MMU-AP0091H service manual Refrigerant Recovery in the Malfunctioning Outdoor Unit, 191

13.REFRIGERANT RECOVERY

WHEN REPLACING THE COMPRESSOR

13-1. Refrigerant Recovery in the Malfunctioning Outdoor Unit

Apump-down function is available in this system. For multiple outdoor unit systems, execute pump-down by using the normal outdoor units and the refrigerant can be recovered from the outdoor unit, which is to be repaired.

13-1-1. Before Refrigerant Recovery Operation

Pay attention to the following items during pump-down operation.

1.The refrigerant recovery rate changes with the outside temperature in the pump-down operation.

When the pump-down operation has finished, recover the remaining gas using a recovery device and measure the amount of recovered refrigerant.

2.Executing the pump-down operation when heating the accumulator of the malfunctioning outdoor unit improves refrigerant recovery rate.

3.While both outdoor PMVs are closed the refrigerant in the heat exchanger cannot be recovered.

If executing brazing after pump-down operation, recover the refrigerant in the heat exchanger before starting.

13-1-2. Refrigerant Recovery Procedure

(If no backup operation for the outdoor unit has been implemented)

Procedure

Turn on the power supply to the system, and ensure system operation is stopped. If the fault is an insulation error in the compressor, remove the wiring to the compressor before turning on the power supply.

[Set up the malfunctioning outdoor unit as follows]

1.Using a charge hose, connect the check joint of the liquid pipe and the check joint at the low pressure side, then purge the air in the hose (to recover refrigerant in the heat exchanger and the liquid tank).

2.Fully close the service valve of the liquid pipe of the malfunctioning outdoor unit. Keep service valves of the gas pipe and the balance pipe open.

3.If it is thought that the oil has deteriorated due to a faulty compressor, take off the SV3A valve connector of the malfunctioning outdoor unit, so that the oil does not flow in the other outdoor units.

4.Set the rotary switches SW01/02/03 to 2/11/1 on the interface P.C. board of the malfunctioning outdoor unit, [rd] [ ] is displayed on the 7-segment display.

5.Press SW04 for 5 seconds or more, [rd][ FF] is displayed on 7-segment display and then pump down starts.

∗When interrupting the operation, turn off the power supplies to all of the outdoor units or push SW05 on the interface P.C. board.

3

If oil deteriorates due to a faulty compressor, remove SV3A connector.

Malfunctioning outdoor unit

1

Connected with check joint of the liquid pipe and check joint at low pressure side by a charge hose and purge.

2

Close fully service valve at liquid side. (Keep gas and balance side opened.)

4 Set rotary SW01/02/03 to 2/11/1.

[rd] [ ] are displayed.
	¯
Push the push SW04 for 5 seconds or more.
5 [rd] [ FF] are displayed.
Operation during pump down operation
Outdoor unit	Operation contents
	Compressor stops.
Outdoor unit with trouble	Outdoor fan ON
	PMV1 and PMV2 open.
	SV3A/3B/3C/3D/3E ON
Other outdoor units	Operates in test COOL operation

P.C. board of the malfunctioning outdoor unit

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