Hitachi RAS-2-HVNP Service Manual page 91

3. Piping work and refrigerant charge
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Setting of pipe length DSW.
DSW2 setting will be required only when the refrigerant pipe length is shorter than 5 m or longer than 30 m. Pipe length
setting shall be performed as shown below.
(The ■ side in the DIP switch show the position.)
Factory setting
Piping length between 5 m and ℓ(m)
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Pump down refrigerant
When the refrigerant should be collected into the outdoor unit due to indoor/outdoor unit relocation, collect the refrigerant
as follows:
1 Attach the manifold gauge to the gas stop valve and the liquid stop valve.
2 Turn ON the power source.
3 Set the DSW1-1 pin of the outdoor unit PCB at the "ON" side for cooling operation. Close the liquid stop valve and col-
lect the refrigerant.
4 When the pressure at lower pressure side (gas stop valve) indicates -0.01 MPa (-100 mmHg), perform the following
procedures immediately.
• Close the gas stop valve.
• Set the DSW1-1 pin at the "OFF" side (To stop the unit operation).
5 Turn OFF the power source.
C A U T I O N
Measure the low pressure by the pressure gauge and keep it in a measurement higher than -0.01 MPa. If the pres-
sure is lower than -0.01 MPa, the compressor may be faulty.
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DSW2 on outdoor PCB1
Pipe Length 5 m or shorter
SMGB0079 rev.0 - 01/2013
Pipe Length 30 m or longer
3