Mitsubishi Electric PUHZ-SW75VHAR6 Service Manual page 5

2-3. PRECAUTIONS WHEN REUSING EXISTING R22 REFRIGERANT PIPES
Flowchart
• Refer to the flowchart below to determine if the existing pipes can be used and if it is necessary to use a filter dryer.
• If the diameter of the existing pipes is different from the specified diameter, refer to technical data materials to confirm if the pipes can be used.
The existing pipe thickness meets specifi-
cations and the pipes are not damaged.
Check if the existing outdoor unit can
operate.
After operating the cooling system for
about 30 minutes, do a pump down work.
Disconnect the existing outdoor unit from
the pipes.
Attach the new outdoor unit
Perform the airtight test, vacuum air
purging, additional refrigerant charging (if
necessary), and gas leak check.
OCH755
Measure the existing pipe thickness
and check for damage.
• If the existing outdoor unit cannot operate,
use a refrigerant recovery device to collect
the refrigerant.
Use new pipes for SW75, SW100 and SW120
models.
5
The existing pipe thickness does not meet
specifications or the pipes are damaged.
The existing pipes cannot be reused.
Use new pipes.