Connecting Refrigerant Pipes And Drain Pipes; Refrigerant Piping Work; Drain Piping Work; Duct Work - Mitsubishi Electric CITY MULTI PEFY-P-VMH-E-F Manual De Instalación

7. Connecting refrigerant pipes and drain pipes

7.1. Refrigerant piping work

This piping work must be done in accordance with the installation manuals for both
outdoor unit and BC controller (simultaneous cooling and heating series R2).
• Series R2 is designed to operate in a system that the refrigerant pipe from an
outdoor unit is received by BC controller and branches at the BC controller to
connect between indoor units.
• For constraints on pipe length and allowable difference of elevation, refer to
the outdoor unit manual.
• The method of pipe connection is flare connection.
Cautions On Refrigerant Piping
s s s s s Be sure to use non-oxidative brazing for brazing to ensure that no for-
eign matter or moisture enter into the pipe.
s s s s s Be sure to apply refrigerating machine oil over the flare connection seat-
ing surface and tighten the connection using a double spanner.
s s s s s 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 pro-
vided 50 cm away from the indoor unit's flare connection.
Warning:
When installing and moving the unit, do not charge it with refrigerant other
than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to mal-
function and result in severe damage.
Caution:
• Use refrigerant piping made of C1220 (Cu-DHP) phosphorus deoxidized
copper as specified in the JIS H3300 "Copper and copper alloy seamless
pipes and tubes". In addition, be sure that the inner and outer surfaces
of the pipes are clean and free of hazardous sulphur, oxides, dust/dirt,
shaving particles, oils, moisture, or any other contaminant.
• Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerator oil
in the existing piping will cause the new refrigerant to deteriorate.

8. Duct work

• When connecting ducts, insert a canvas duct between the main body and the
duct.
• Use non-combustible duct components.
• Install sufficient thermal insulation to prevent condensation forming on air inlet
and air outlet duct flanges, and air outlet ducts.
[Fig. 8.0.1] (P. 4)
A Air inlet
C Duct

9. Electrical wiring

Precautions on electrical wiring
Warning:
Electrical work should be done by qualified electrical engineers in accord-
ance with "Engineering Standards For Electrical Installation" and supplied
installation manuals. Special circuits should also be used. If the power cir-
cuit lacks capacity or has an installation failure, it may cause a risk of elec-
tric shock or fire.
1. Be sure to take power from the special branch circuit.
2. Be sure to install an earth leakage breaker to the power.
3. Install the unit to prevent that any of the control circuit cables (remote control-
ler, transmission cables) is brought in direct contact with the power cable out-
side the unit.
4. Ensure that there is no slack on all wire connections.
B Air filter (supplied at site)
D Canvas duct
• Store the piping to be used during installation indoors and keep both
ends of the piping sealed until just before brazing.
- If dust, dirt, or water gets into the refrigerant cycle, the oil will deteriorate and
the compressor may fail.
• Use ester oil, ether oil or alkylbenzene (small amount) as the refrigerator
oil to coat flares and flange connections. (For models using R410A or
R407C)
- The refrigerant used in the unit is highly hygroscopic and mixes with water
and will degrade the refrigerator oil.

7.2. Drain piping work

1. Ensure that the drain piping is downward (pitch of more than 1/100) to the
outdoor (discharge) side. Do not provide any trap or irregularity on the way.
(1)
2. Ensure that any cross-wise drain piping is less than 20 m (excluding the differ-
ence of elevation). If the drain piping is long, provide metal braces to prevent it
from waving. Never provide any air vent pipe. Otherwise drain may be ejected.
3. Use a hard vinyl chloride pipe VP-25 (with an external diameter of 32 mm) for
drain piping.
4. Ensure that collected pipes are 10 cm lower than the unit body's drain port as
shown in 2.
5. Do not provide any odor trap at the drain discharge port.
6. Put the end of the drain piping in a position where no odor is generated.
7. Do not put the end of the drain piping in any drain where ionic gases are
generated.
[Fig. 7.2.1] (P. 4)
A Downward slope 1/100 or more
B Drain hose (Accessory)
C Indoor unit
D Collective piping
E Maximize this length to approx. 10 cm
E Access door
G Ensure sufficient length to prevent short cycling
H Air outlet
I Keep duct-work length 850 mm or more
Caution:
Inlet duct is 850 mm or more necessary to construct.
Always install horizontal.
5. Some cables (power, remote controller, transmission cables) above the ceiling
may be bitten by mouses. Use as many metal pipes as possible to insert the
cables into them for protection.
6. Never connect the power cable to leads for the transmission cables. Other-
wise the cables would be broken.
7. Be sure to connect control cables to the indoor unit, remote controller, and the
outdoor unit.
8. Put the unit to the ground on the outdoor unit side.
9. Select control cables from the conditions given in page 10 .
Caution:
• Be sure to put the unit to the ground on the outdoor unit side. Do not
connect the earth cable to any gas pipe, water pipe, lightening rod, or
telephone earth cable. Incomplete grounding may cause a risk of electric
shock.
• If the supply cord is damaged, it must be replaced by the manufacturer,
its service agent or similarly qualified persons in order to avoid a hazard.
F Ceiling
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