Mitsubishi Electric Mr.Slim PEY-SM18JA-PA/VN Installation Manual page 18

6.3. Pipe connection
[Fig. 6-8] (P.4)
A Flare cutting dimensions
D Flare nut tightening torque
• Flare the ends of the refrigerant pipes. A
• Apply refrigerating machine oil over the entire flare seat surface. B
• Use the flare nuts as follows. C
• For connection, first align the center, then tighten the first 3 to 4 turns of flare nut
by hand.
• Use 2 wrenches to tighten piping connections. D
• Use leak detector or soapy water to check for gas leaks after connections are
completed.
• Use tightening torque table below as a guideline for indoor unit side union joint
section, and tighten using two wrenches. Excessive tightening damages the flare
section.
Copper pipe O.D. Flare nut O.D.
(mm)
ø6.35
ø9.52
ø12.7
ø15.88
Warning:
Be careful of flying flare nut! (Internally pressurized)
Remove the flare nut as follows:
1. Loosen the nut until you hear a hissing noise.
2. Do not remove the nut until the gas has been completely released (i.e.,
hissing noise stops).
3. Check that the gas has been completely released, and then remove the
nut.
Outdoor unit connection
Connect pipes to stop valve pipe joint of the outdoor unit in the same manner
applied for indoor unit.
• For tightening use a torque wrench or spanner, and use the same tightening
torque applied for indoor unit.
Refrigerant pipe insulation
• After connecting refrigerant piping, insulate the joints (flared joints) with thermal
insulation tubing.
[Fig. 6-9] (P.4)
A Pipe cover (small) (accessory)
B Caution:
Pull out the thermal insulation on the refrigerant piping at the site, insert the flare nut
to flare the end, and replace the insulation in its original position.
Take care to ensure that condensation does not form on exposed copper piping.
C Liquid end of refrigerant piping
E Site refrigerant piping
G Pipe cover (large) (accessory)
I Pull
K Return to original position
M Plate on main body
O Ensure that there is no gap here. Place join upwards.
1. Remove and discard the rubber bung which is inserted in the end of the unit
piping.
2. Flare the end of the site refrigerant piping.
3. Pull out the thermal insulation on the site refrigerant piping and replace the
insulation in its original position.
Cautions On Refrigerant Piping
 Be sure to use non-oxidative brazing for brazing to ensure that no foreign
matter or moisture enter into the pipe.
 Be sure to apply refrigerating machine oil over the flare connection
seating surface and tighten the connection using a double spanner.
 Provide a metal brace to support the refrigerant pipe so that no load is
imparted to the indoor unit end pipe. This metal brace should be provided
50 cm away from the indoor unit's flare connection.
18
Tightening torque
(mm) (N·m)
17 14 - 18
22 34 - 42
26 49 - 61
29 68 - 82
D Gas end of refrigerant piping
F Main body
H Thermal insulation (field supply)
J Flare nut
L Ensure that there is no gap here
N Band (accessory)
6.4. Purging procedures leak test
PURGING PROCEDURES
Connect the refrigerant pipes (both the liquid and gas pipes) between the indoor
and the outdoor units.
Remove the service port cap of the stop valve on the side of the outdoor unit gas pipe.
(The stop valve will not work in its initial state fresh out of the factory (totally
closed with cap on).)
Connect the gage manifold valve and the vacuum pump to the service port of the
stop valve on the gas pipe side of the outdoor unit.
Run the vacuum pump. (Vacuumize for more than 15 minutes.)
Check the vacuum with the gage manifold valve, then close the gage manifold
valve, and stop the vacuum pump.
Leave it as is for one or two minutes. Make sure the pointer of the gage manifold
valve remains in the same position. Confirm that the pressure gage show
-0.101MPa (-760 mmHg).
Stop valve
*Close
Stop valve
*Open
Hexagonal wrench
Service port
*4 to 5 turns
Remove the gage manifold valve quickly from the service port of the stop valve.
After refrigerant pipes are connected and evacuated, fully open all stop valves
on gas and liquid pipe sides.
Operating without fully opening lowers the performance and causes trouble.
Pipe length:
7 m maximum
No gas charge is needed.
Tighten the cap to the service port to obtain the initial status.
Retighten the cap
Leak test
-0.101MPa
(-760 mmHg) Compound pressure gauge
Pressure gauge
(for R32)
Gauge manifold
valve (for R32)
Handle High
Handle
Low
Charge hose
Stop
(for R32)
valve
(or the vacuum
Vacuum
pump
pump with the
Window
function to
Adapter for
prevent the back
Charge hose
preventing the
flow)
(for R32)
back flow
Pipe length exceeding 7 m
Charge the prescribed
amount of gas.