Mitsubishi Electric Mr.SLIM SUZ-KA71VA Installation Manual page 5

5. Refrigerant piping work
a b
B
d
c
Fig. 5-8
5.5. 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 -0.101
MPa (-760 mmHg)
Stop valve
*Close
Stop valve
*Open
Hexagonal wrench
Service port
*4 to 5 turns
e f g h
i
Fig. 5-7
Compound pressure
-0.101 MPa
gauge (for R410A)
(-760 mmHg)
Pressure gauge
(for R410A)
Gauge manifold
valve (for R410A)
Handle High
Handle
Low Charge hose
Stop
(for R410A)
valve
(or the vacuum
Vacuum
pump
pump with the
Window
function to
Adapter for
prevent the back
Charge hose
preventing
flow)
(for R410A)
the back flow
5.2.5. Check (Fig. 5-7)
• Compare the flared work with a figure in right side hand.
• If flare is noted to be defective, cut off the flared section and do flaring work again.
a Smooth all around
b Inside is shining without any scratches
c Even length all around
d Too much
e Tilted
• Apply a thin coat of refrigeration oil on the seat surface of pipe. (Fig. 5-8)
• For connection first align the center, then tighten the first 3 to 4 turns of flare nut.
• 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., hiss-
ing noise stops).
3. Check that the gas has been completely released, and then remove the nut.
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
f Scratch on flared plane
g Cracked
h Uneven
i Bad examples
Tightening torque
(mm) (N·m)
17 14 - 18
22 34 - 42
26 49 - 61
29 68 - 82
Pipe length exceeding 7 m
Charge the prescribed
amount of gas.
Leak test
5