Precautions When Reusing Existing R22 Refrigerant Pipes - Mitsubishi Electric PUHZ-RP200 Installation Manual

5. Installing the refrigerant piping

5.7. Precautions when reusing existing R22 refrigerant pipes

• Refer to the flowchart below to determine if the existing pipes can be used.
• See below for oil condition.
Clear to slight yellow color → Normal
Black or brown → Pipe cleaning is necessary.
• 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.
• Additional charge amount for 70 m.
The existing pipe thickness meets specifi-
cations and the pipes are not damaged.
Check if the existing air conditioner can operate.
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.
The existing piping can be reused.
After flaring the pipes again, connect the
new air conditioner.
Perform the following inspections: air
tightness test, vacuum dryness (additional
refrigerant charge), gas leakage check
Replacement operation
Test operation
<Limits of refrigerant piping installation>
A
B
E
A
C
D
A
B
≤
• A+B+C(+D) 120 m * "D" is for triple.
≤
• A+B+C(+E) 120 m * "E" is for four (quadruple).
Fig. 5-8
10
Measure the existing pipe thickness and check
for damage.
The existing air conditioner cannot operate.
Use a refrigerant collecting device to collect the refrigerant.
Check the oil condition when collecting the refrigerant.
Oil is clean. (Clear to brownish color)
* Refer to 12 page
C
A
D
A Indoor unit
B Outdoor unit
A
E
C Multi distribution pipe (option)
D Height difference (Indoor unit-
Outdoor unit) Max. 40 m
E Height difference (Indoor unit-
Indoor unit) Max. 1 m
A: Main piping
B, C, D, E: Branch piping
B–C A+B
≤
B–D 8 m A+C
Max. 100 m
C–D A+D
A+E
The existing pipe thickness does not meet
specifications or the pipes are damaged.
Oil is dirty. (Black color)
When the compressor bearings are
glazed, rotation scratches are present,
or the compressor breaks down, iron
particles or oil deterioration will blacken
the oil.
5.8. For twin/triple/quadruple combination (Fig. 5-8)
• When this unit is used as a FREE COMPO MULTI unit, install the refrigerant piping
with the restrictions indicated in the drawing on the left. In addition, if the restric-
tions are going to be exceeded, or if there are going to be combinations of indoor
and outdoor units, refer to installation instructions for the indoor unit for details
about the installation.
Permissible total
Outdoor unit piping length
A+B+C+D+E
RP200
120 m and less
RP250
B-C or B-D or
Outdoor unit B-E or C-D or
C-E or D-E
RP200
8 m and less
RP250
The existing pipes cannot be reused.
Use new pipes.
A+B or A+C Charge-less
or piping length
A+D or A+E A+B+C+D+E
100 m and less 30 m and less
No. of bends
Within 15