Precautions When Reusing Existing R22 Refrigerant Pipes - Mitsubishi Electric PUHZ-FRP71VHA Service Manual

2-3. PRECAUTIONS WHEN REUSING EXISTING R22 REFRIGERANT PIPES

(1) Flowchart
• Refer to the f owchart below to determine if the existing pipes can be used and if it is necessary to use a f lter dryer.
• If the diameter of the existing pipes is different from the specif ed diameter, refer to technological data materials to conf rm if
the pipes can be used.
The existing pipe thickness meets specif ca-
tions and the pipes are not damaged.
▼
Check if the existing air conditioner can operate.
▼
After operating the cooling system for about 30
minutes, do a pump down work.
▼
Disconnect the existing air conditioner from the
pipes.
▼
Attach the new air conditioner
▼
Perform the airtight test, vacuum air purging,
additional refrigerant charging (if necessary),
and gas leak check.
▼
Test run
OCH544
Measure the existing pipe thickness and
check for damage.
* If the existing air conditioner cannot operate, use a
refrigerant recovery device to collect the refrigerant.
* If the existing pipes have been used for gas or oil
heat pump system, use new pipes.
5
The existing pipe thickness does not meet
specif cations or the pipes are damaged.
▼
The existing pipes cannot be reused.
Use new pipes.