Mitsubishi Electric SUHZ-SW VA series Installation Manual page 5

5. Refrigerant piping work
B
a b
c
Fig. 5-7
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 gauge 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 gauge manifold valve, then close the gauge manifold
valve, and stop the vacuum pump.
Leave it as is for one or two minutes. Make sure the pointer of the gauge mani-
fold valve remains in the same position. Confirm that the pressure gauge shows
-0.101 MPa (-760 mmHg).
Stop valve
*Close
Stop valve
*Open
Hexagonal wrench
Service port
*4 to 5 turns
d e f g h
i
-0.101 MPa Compound pressure
(-760 mmHg) gauge (for R410A)
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 prevent
the back flow)
Adapter for
Charge hose
preventing the
(for R410A)
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.
Smooth all around
a
Inside is shining without any scratches
b
Even length all around
c
Too much
d
Tilted
e
• 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:
When installing the unit, securely connect the refrigerant pipes before starting
the compressor.
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 gauge 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.
Scratch on flared plane
f
Cracked
g
Uneven
h
Bad examples
i
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