Maintenance - Mitsubishi Electric American Standard NAXSKS18A112A Série Manuel D'installation

5. Electrical work
5.2. Field electrical wiring
Outdoor unit model
Power supply
Max. Fuse size (time delay)
Min. Circuit Ampacity
Outdoor unit power supply
Outdoor unit power supply earth
Indoor unit-Outdoor unit
Indoor unit-Outdoor unit ground
Outdoor unit L1-L2
Indoor unit-Outdoor unit S1-S2
Indoor unit-Outdoor unit S2-S3
*1. Please follow applicable federal, state, or local codes to prevent potential leakage/electric shock. Or install a ground fault interrupt for the prevention of leakage and electric shock.
*2. The figures are NOT always against the ground.
S3 terminal has 24 VDC against S2 terminal. However between S3 and S1, these terminals are NOT electrically insulated by the transformer or other device.
Notes: 1. Wiring size must comply with the applicable local and national code.
2. Use copper supply wires.
3. Use wires rated 600V or more for the power supply cables and the indoor/outdoor unit connecting cables.
4. Install an earth longer than other cables.
Warning:
In case of A-control wiring, there is high voltage potential on the S3 terminal caused by electrical circuit design that has no electrical insulation between power
line and communication signal line. Therefore, please turn off the main power supply when servicing. And do not touch the S1, S2, S3 terminals when the power
is energized. If isolator should be used between indoor unit and outdoor unit, please use 3-pole type.

6. Maintenance

B
A
C
D
G
L
K
H
I
J
Indoor unit
A H
Union
B I
Liquid pipe
C J
Gas pipe
D K
Stop valve
E L
Outdoor unit
F M
Refrigerant gas cylinder
G
operating valve
Fig. 6-1
NAXSKS18A112A
~/N (single), 60 Hz 208/230 V
*1
2 × Min. AWG 14
1 × Min. AWG 14
3 × AWG 14 (Polar)
1 × Min. AWG 16
*2 208/230 VAC
*2 208/230 VAC
*2 12 VDC - 24 VDC (Polar)
208/230V
Single phase
Isolator
S1
A-Control
S2
Outdoor Unit
S3
E
F
M
Refrigerant gas cylinder for R410A with siphon
Refrigerant (liquid)
Electronic scale for refrigerant charging
Charge hose (for R410A)
Gauge manifold valve (for R410A)
Service port
NAXSKS24A112A
NAXSKS30A112A
NAXSKS36A112A
~/N (single), 60 Hz 208/230 V
15 A
14 A
2 × Min. AWG 14
1 × Min. AWG 14
3 × AWG 14 (Polar)
1 × Min. AWG 16
12 VDC - 24 VDC (Polar)
3 poles isolator
6.1. Gas charge (Fig. 6-1)
1. Connect gas cylinder to the service port of stop valve (3-way).
2. Execute air purge of the pipe (or hose) coming from refrigerant gas cylinder.
3. Replenish specified amount of refrigerant, while running the air conditioner for
cooling.
Note:
In case of adding refrigerant, comply with the quantity specified for the refrig-
erating cycle.
Caution:
• Do not discharge the refrigerant into the atmosphere.
Take care not to discharge refrigerant into the atmosphere during installa-
tion, reinstallation, or repairs to the refrigerant circuit.
• For additional charging, charge the refrigerant from liquid phase of the gas
cylinder.
If the refrigerant is charged from the gas phase, composition change may
occur in the refrigerant inside the cylinder and the outdoor unit. In this case,
ability of the refrigerating cycle decreases or normal operation can be im-
possible. However, charging the liquid refrigerant all at once may cause the
compressor to be locked. Thus, charge the refrigerant slowly.
To maintain the high pressure of the gas cylinder, warm the gas cylinder with warm
water (under 104 °F, 40 °C) during cold season. But never use naked fire or steam.
20 A
17 A
208/230 VAC
208/230 VAC
S1
A-Control
S2
Indoor Unit
S3
7