De Dietrich AWHP 4 MR Manuel D'installation page 8

4. Installing the refrigerant piping
4.7. Precautions when reusing existing R22 refrigerant pipes
• Refer to the fl owchart below to determine if the existing pipes can be used and if it is necessary to use a fi lter dryer.
• If the diameter of the existing pipes is different from the specifi ed diameter, refer to technological data materials to confi rm if the pipes can be used.
The existing pipe thickness meets specifi ca-
tions 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.
▼
Test run
* Refer to 6.2.
8
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.
* In case existing pipes were used for gas or oil
heat pump systems, be sure to clean the pipes
for AWHP11, 16 models.
Use new pipes for AWHP4-8 models.
The existing pipe thickness does not meet
specifi cations or the pipes are damaged.
▼
The existing pipes cannot be reused.
Use new pipes.