Replacement of Main Units
TD831077
VII-4
7
(1) Refrigerant Recovery and Oil Recovery of the Faulty Unit
(Always use the refrigerant recovery device)
Dirty oil and refrigerant from the faulty unit must not be recovered in another unit. Use the following procedure to
correctly perform refrigerant and oil recovery. Also, be sure to connect the dry core (D-253U) in accordance with Fig. A
(P19).
1. Perform an air purge for each service pipe. (Do not release the refrigerant into the open air.)
Install a manual valve (packless valve) near the connected piping discharge outlet, and then perform an air purge
for the piping up to the valve. Use a vacuum pump to air purge with a vacuum pump up to 133.3 Pa (1 mmHg) in
the connected main piping. Also, air purge with a vacuum pump inside the oil separator.
2. Set the valves.
Open valves V1 and V5, and close the other valves V2, V3, V4, V6, V7, V8, and V9. (The supplied valves of the oil
tank and oil separator are all closed.)
3. Operate the refrigerant recovery device, and recover the dirty refrigerant.
* For information about refrigerant recovery device operation, refer to the operation manual of the respective
device. Prepare a cylinder with a capacity of at least 15 kg.
4.
Look at the site glass, and perform the valve operations below to recover the oil if the liquid refrigerant
becomes low.
a) Close the valves of the balance pipes (1 valve).
b) Set the balance pipe valve 2 of the faulty outdoor unit from closed to the half-way open (turn about two times).
c) Perform operations on the valves installed at the site. Open the V2 and V4 oil separator valves, and set the V1
valve from open to closed. (Oil recovery is started.)
d) When approximately 10 minutes elapses, turn valve V1 from closed to open, and then operate until the low-
pressure switch of the refrigerant recovery device is activated.
(Perform refrigerant and oil recovery until the internal pressure of the faulty unit is 0.098 MPa (1 kg/cm
2
) or
lower. If the dry core is clogged with dirt or other debris, replace it with a new one.)
5. Stop operation of the refrigerant recovery device.
6. Close the V5 valve, and then open the V9 valve to release the small amount of residual gas refrigerant into
a safe location. Check that the vacuum low-pressure gauge becomes 0 MPa (0 kg/cm
2
).
7. When these operations are finished, remove the circuits for the oil separator, dry core, and V4 valve.
8. Measure the amount of recovered refrigerant and oil. (This amount of refrigerant and oil will be added
later.)
9. Never attempt to reuse recovered refrigerant or oil. Dispose of the recovered refrigerant and oil at a recy-
cling plant.
1. Compressors
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