4
2-3. PRECAUTIONS WHEN REUSING EXISTING R22 REFRIGERANT PIPES
(1) Flowchart
(2) Cautions for refrigerant piping work
New refrigerant R410A is adopted for replacement inverter series. Although the refrigerant piping work for R410A is same
as for R22, exclusive tools are necessary so as not to mix with different kind of refrigerant. Furthermore as the working
pressure of R410A is 1.6 times higher than that of R22, their sizes of flared sections and flare nuts are different.
1
Thickness of pipes
Because the working pressure of R410A is higher compared to R22, be sure to use refrigerant piping with thickness
shown below. (Never use pipes of 0.7 mm or below.)
1/4
3/8
1/2
5/8
3/4
6.35
9.52
12.70
15.88
19.05
0.8
0.8
0.8
1.0
—
0.8
0.8
0.8
1.0
1.0
Nominal
dimensions (in)
Diagram below: Piping diameter and thickness
Outside
diameter (mm)
Thickness (mm)
R410A
R22
[3] Service tools
Use the below service tools as exclusive tools for R410A refrigerant.
No.
Tool name
Specifications
1
Gauge manifold
·
Only for R410A
·
Use the existing fitting specifications. (UNF1/2)
·
Use high-tension side pressure of 5.3MPa·G or over.
2
Charge hose
·
Only for R410A
·
Use pressure performance of 5.09MPa·G or over.
3
Electronic scale
—
4
Gas leak detector
·
Use the detector for R134a, R407C or R410A.
5
Adaptor for reverse flow check
·
Attach on vacuum pump.
6
Refrigerant charge base
—
7
Refrigerant cylinder
·
Only for R410A
·
Top of cylinder (Pink)
·
Cylinder with syphon
8
Refrigerant recovery equipment
—
Perform the airtight test, vacuum air purging,
additional refrigerant charging (if necessary),
and gas leak check.
• Refer to the flowchart below to determine if the existing pipes can be used and if it is necessary to use a filter drier.
• If the diameter of the existing pipes is different from the specified diameter, refer to technological data materials to confirm if
the pipes can be used.
Measure the existing pipe thickness and
check for damage.
The existing pipe thickness meets specifica
-
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
The existing pipes cannot be reused.
Use new pipes.
• If the existing air conditioner 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.
The existing pipe thickness does not meet
specifications or the pipes are damaged.
OCH583
