Mitsubishi Heavy Industries SRK63ZR-WF Technical Manual page 33

4. CONNECTING PIPING WORK
1. Restrictions on unit installation
Abide by the following restrictions on unit installation.
Improper installation can cause compressor failure or performance degradation.
Dimensional
restrictions
Connecting pipe length(L) 30m or less
Elevation difference between
20m or less
indoor and outdoor units(H)*
* Outdoor unit installation position can be higher as well as lower than the indoor unit installation position.
2. Preparation of connecting pipe
2.1. Selecting connecting pipe
Select connecting pipe according to the following table.
Model SRC63
G a s p p i e ø 1
L q i u d i p p i e ø 6
• Pipe wall thickness must be greater than or equal to 0.8 mm (ø15.88:1.0mm).
• Pipe material must be O-type (Phosphorus deoxidized seamless copper pipe ICS 23.040.15, ICS
77.150.30).
NOTE
If it is required to reuse the existing connecting pipe system, refer to 5. UTILIZATION OF EXISTING PIPE.
2.2. Cutting connecting pipe
(1) Cut the connecting pipe to the required length with pipe cutter.
(2) Hold the pipe downward and remove the burrs. Make sure that no foreign material enters the pipe.
(3) Cover the connecting pipe ends with the tape.
3. Piping work
Check that both liquid and gas operation valves are fully closed.
Carry out the piping work with operation valves fully closed.
3.1. Flaring pipe
(1) Take out are nuts from the operation valves of outdoor unit and engage them onto connecting pipes.
(2) Flare the pipes according to table and gure shown below.
Flare dimensions for R32 are different from those for conventional refrigerant.
Although it is recommended to use the aring tools designed speci cally for R32 or R410A, conventional
aring tools can also be used by adjusting the dimension B with a are adjustment gauge.
A
Copper pipe
A
outer diameter
ø . 6 5 3 9 1 .
ø 2 1 7 . 6 1 6 .
1 ø . 5 8 8 9 1 7 .
3.2. Connecting pipes
(1) Connect pipes on both liquid and gas sides.
(2) Tighten nuts to speci ed torque shown in the table below.
Operation valve size (mm) Tightening torque (N·m)
ø6.35 (1/4")
ø12.7 (1/2")
ø15.88 (5/8")
CAUTION
• Do not apply refrigerating machine oil to the ared surface. It can cause refrigerant leakage.
• Do not apply excess torque to the ared nuts. The ared nuts may crack resulting in refrigerant leakage.
5. UTILIZATION OF EXISTING PIPE
(1) Check whether an existing pipe system is reusable or not by using the following ow chart.
Are the outdoor and indoor units connected to the existing pipe system ?
YES
Is it possible to run the unit ?
YES
Does the existing unit use any of the following refrigerant oils ?
Suniso, MS,Barell Freeze, HAB, Freol, ether oil, ester oil.
YES
Do the existing pipe speci cations (pipe length, pipe size and elevation difference between indoor and outdoor unit) conform to the restric-
tion of the unit.? (Go to 4.Connecting piping work and check 1.Restrictions on unit installation and 2.Preparation of connecting pipe.)
YES
Is the existing pipe system free of corrosion, aws and dents?
YES
Is the existing pipe system free of gas leaks?
(Check whether refrigerant charge was required
frequently for the system before.)
YES
Are heat insulation materials of the existing pipe system
free of peel-off or deterioration?
(Heat insulation is necessary for both gas and liquid pipes.)
YES
Is the existing piping system free of any loose pipe support ?
YES
The existing pipe system is reusable.
RCT012A220.indd 2
H
Model SRC71/80
2 7 . ø 1 5 8 . 8
3 . 5 ø 6 3 . 5
Liquid operation valve
Gas operation valve
Copper pipe
outer diameter
ø . 6 5 3
ø 2 1 7 .
1 ø . 5 8 8
14-18
49-61
68-82
Do not hold the valve cap area with a spanner
NO
NO
NO
NO
Repair is impossible.
NO
Repair the damaged parts.
Repair
Air tightness is
impossible.
NO
Check the pipe system for air tightness.
Air tightness is OK.
Repair is impossible.
NO
Repair the damaged parts.
Repair
NO
Repair the loose pipe support.
Repair
The existing pipe system is not reusable.
Install the new pipe system.
4. Evacuation
(1) Connect vacuum pump to gauge manifold. Connect charge hose of gauge manifold to service port
of outdoor unit.
(2) Run the vacuum pump for at least one hour after the vacuum gauge shows -0.1MPa (–76cm Hg).
(3) Con rm that the vacuum gauge indicator does not rise even if the system is left for 15 minutes or more.
Vacuum gauge indicator will rise if the system has moisture left inside or has a leakage point.
Check the system for the leakage point. If leakage point is found, repair it and return to (1) again.
(4) Close the Handle Lo and stop the vacuum pump.
Keep this state for a few minutes to make sure that the compound pressure gauge pointer does not
L
swing back.
(5) Remove valve caps from liquid operation valve and gas operation valve.
(6) Turn the liquid operation valve's rod 90 degree counterclockwise with a hexagonal wrench key to
open valve.
Close it after 5 seconds, and check for gas leakage.
Using soapy water, check for gas leakage from indoor unit's are and outdoor unit's are and valve rods.
Wipe off all the water after completing the check.
(7) Disconnect charging hose from gas operation valve's service port and fully open liquid and gas op-
eration valves. (Do not attempt to turn valve rod beyond its stop.)
(8) Tighten operation valve caps and service port cap to the speci ed torque shown in the table below.
Operation valve size (mm)
ø 6 3 . 5 1 (
ø 1 2 7 . 1 (
ø 1 5 8 . 8 5 (
CAUTION
To prevent vacuum pump oil from entering into the refrigerant system, use a counter ow prevention adapter.
5. Additional refrigerant charge
Additional refrigerant charge is required only when connecting pipe length exceeds 15 m.
5.1 Calculating additional refrigerant charge
Additional refrigerant charge can be calculated using the formula given below.
<SRC63>
Additional refrigerant charge (g) = { Connecting pipe length (m) – Factory charged length 15 (m) } x 20 (g/m)
<SRC71/80>
Additional refrigerant charge (g) = { Connecting pipe length (m) – Factory charged length 15 (m) } x 25 (g/m)
NOTE
• If additional refrigerant charge calculation result is negative, there is no need to remove the refrigerant.
B [Rigid (clutch) type]
• If refrigerant recharge is required for the unit with connecting pipe length 15m or shorter, charge the
factory charged amount as shown in the table below.
R32 or
Conventional
R410A
T h e a f c o t y r e r r f g i e
0-0.5 1.0-1.5
T h e m a i x m u m e r r f g i
5.2 Charging refrigerant
(1) Charge the R32 refrigerant in liquid phase from service port with both liquid and gas operation
valves shut. Since R32 refrigerant must be charged in the liquid phase, make sure that refrigerant is
discharged from the cylinder in the liquid phase all the time.
(2) When it is dif cult to charge a required refrigerant amount, fully open both liquid and gas opera-
tion valves and charge refrigerant, while running the unit in the cooling mode. When refrigerant is
charged with the unit being run, complete the charge operation within 30 minutes.
(3) Write the additional refrigerant charge calculated from the connecting pipe length on the label at-
tached on the service cover.
CAUTION
• Running the unit with an insuf cient quantity of refrigerant for a long time can cause unit malfunction.
• Do not charge more than the maximum refrigerant amount. It can cause unit malfunction.
NOTE
• Consult with our distributor in the area, if you need to recover refrigerant and charge it again.
(2) Clean the existing pipe system according to the procedure given below.
(a) Carry out forced cooling operation of existing unit for 30 minutes.
For 'Forced cooling operation' refer to the indoor unit installation manual.
(b) Stop the indoor fan and carry out forced cooling operation for 3 minutes (Liquid return).
(c) Close the liquid operation valve of the outdoor unit and carry out pump down operation (Refer to 6.
PUMP DOWN).
(d) Blow with nitrogen gas. If discolored refrigeration oil or any foreign matter is discharged by the
blow, wash the pipe system or install a new pipe system.
(3) Remove the are nuts from the existing pipe system. Go back to 4.CONNECTING PIPING WORK
and proceed to step 2.2 Cutting connecting pipe.
CAUTION
• Do not use the old are nuts (of existing unit). Make sure that the are nuts supplied with the (new)
outdoor unit are used.
• If the ared / compression connection to the indoor unit is located inside the house / room then this
pipework can't be reused.
* If the existing piping is speci ed as liquid pipe ø9.52 or gas pipe ø12.7, refer to the following.
<Table of pipe size restrictions>
Additional charge volume per meter of pipe
L q i u
Pipe size
G a s
M a i x m u m o n - e w a y p
L e n g h t c o v e e r d i w h t
Additional charge volume (g) = {Main pipe length (m) - Length covered without additional
charge shown in the table (m)} X Additional charge amount per meter of pipe shown in the table (g/m)
32
- -
Operation valve cap tightening
torque (N·m)
4 / ) " 2 0 3 - 0
2 / ) " 2 5 3 - 5
8 / ) " 3 0 4 - 0
Handle Lo
Liquid operation valve
Valve cap
Gas operation valve
Service port
Charge hose
Model SRC63
a r t n c h a g r e a m o u t n k ( ) g 1 2 . 5
e a r t n c h a g r e a m o u t n k ( ) g 1 5 . 5
Model SRC63
54g/m
d i p p i e ø 9 5 . 2
p p i e ø 1 2 7 .
p i e e l n g h t 1 0
o t u a d d t i o i n a c l h a g r e 5
'22 • SRK-T-362
Service port cap tightening
torque (N·m)
10-12
Compound pressure gauge
Pressure gauge
Gauge manifold
Handle Hi
Vacuum pump
Model SRC71/80
1.50 (71), 1.60 (80)
1 9 . 7 5
Model SRC71/80
54g/m
ø 9 5 . 2
ø 1 5 8 . 8
1 2
6
6
7
8
9