Wiring Of Main Power Supply And Equipment Capacity; Test Run; Before Test Run - Mitsubishi Electric CITY MULTI PUMY-P YHM-Serie Installationshandbuch

6. Electrical work

6.4. Wiring of main power supply and equipment capacity

Schematic Drawing of Wiring (Example) (Fig. 6-4)
A
B
3N~ 400 V
A
~/N 220 - 240 V
D
Thickness of Wire for Main Power Supply and On/Off Capacities
Power Supply
Model
P100-140
Outdoor Unit 3N~ 400V, 50Hz
Indoor Unit
~/N 230V, 50Hz
*1. A breaker with at least 3.0 mm contact separation in each poles shall be provided. Use non-fuse breaker (NF) or earth leakage breaker (NV).
1. Use a separate power supply for the outdoor unit and indoor unit.
2. Bear in mind ambient conditions (ambient temperature,direct sunlight, rain water,etc.) when proceeding with the wiring and connections.
3. The wire size is the minimum value for metal conduit wiring. The power cord size should be 1 rank thicker consideration of voltage drops.
Make sure the power-supply voltage does not drop more than 10 %.
4. Specific wiring requirements should adhere to the wiring regulations of the region.
5. Power supply cords of parts of appliances for outdoor use shall not be lighter than polychloroprene sheathed flexible cord (design 245 IEC57). For example,
use wiring such as YZW.
6. Install an earth longer than other cables.
Warning:
• Be sure to use specified wires to connect so that no external force is imparted to terminal connections. If connections are not fixed firmly, it may cause
heating or fire.
• Be sure to use the appropriate type of overcurrent protection switch. Note that generated overcurrent may include some amount of direct current.
Caution:
• Some installation site may require attachment of an earth leakage breaker. If no earth leakage breaker is installed, it may cause an electric shock.
• Do not use anything other than breaker and fuse with correct capacity. Using fuse and wire or copper wire with too large capacity may cause a malfunction
of unit or fire.
IMPORTANT
Make sure that the current leakage breaker is one compatible with higher harmonics.
Always use a current leakage breaker that is compatible with higher harmonics as this unit is equipped with an inverter.
The use of an inadequate breaker can cause the incorrect operation of inverter.

7. Test run

7.1. Before test run

s After completing installation and the wiring and piping of the indoor and
outdoor units, check for refrigerant leakage, looseness in the power supply
or control wiring, wrong polarity, and no disconnection of one phase in the
supply.
s Use a 500-volt M-ohm tester to check that the resistance between the power
supply terminals and ground is at least 1 MΩ Ω Ω Ω Ω .
s Do not carry out this test on the control wiring (low voltage circuit) termi-
nals.
Warning:
Do not use the air conditioner if the insulation resistance is less than 1 MΩ Ω Ω Ω Ω .
Insulation resistance
After installation or after the power source to the unit has been cut for an extended
period, the insulation resistance will drop below 1 MΩ due to refrigerant accumulat-
ing in the compressor. This is not a malfunction. Perform the following procedures.
1. Remove the wires from the compressor and measure the insulation resistance of
the compressor.
2. If the insulation resistance is below 1 MΩ, the compressor is faulty or the resist-
ance dropped due the accumulation of refrigerant in the compressor.
10
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A : Switch (Breakers for Wiring and Current Leakage)
B : Outdoor Unit
C : Pull Box
D : Indoor Unit
C
D D
Fig. 6-4
Minimum Wire Thickness (mm
Main Cable Branch
1.5 –
1.5 1.5
D
2
) Breaker for
Wiring*1
Ground
1.5
16 A
1.5
15 A
3. After connecting the wires to the compressor, once operating, measure the insu-
lation resistance again.
• The insulation resistance drops due to accumulation of refrigerant in the com-
pressor. The refrigerant collected in the compressor is discharged by operating
at once.
4. If the insulation resistance rises above 1 MΩ, the compressor is not faulty.
Caution:
• The compressor will not operate unless the power supply phase connection
is correct.
s The followings must be checked as well.
• The outdoor unit is not faulty. LED on the control board of the outdoor unit flash
when the outdoor unit is faulty.
• Both the gas and liquid stop valves are completely open.
Breaker for Current Leakage
16 A 30 mA 0.1 sec. or less
15 A 30 mA 0.1 sec. or less