Connecting Refrigerant Pipes And Drain Pipes; Refrigerant Piping Work; Drain Piping Work; Duct Work - Mitsubishi Electric PEFY-P-NMHU-E Manuel D'installation

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 (only 15~54).
• The method of pipe connection is brazing connection (only 72 · 96).
Cautions On Refrigerant Piping
Be sure to use non-oxidative brazing for brazing to ensure that no for-
eign matter or moisture enter into the pipe.
Be sure to apply refrigerating machine oil over the flare connection
seating surface and tighten the connection using a double spanner.
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 [19-11/16 in] away from the indoor unit's flare connection.
Warning:
When installing and moving the unit, do not charge it with a refrigerant
other than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to
malfunction 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 seam-
less pipes and tubes". In addition, be sure that the inner and outer sur-
faces 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. 5)
Air inlet
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.
5. Some cables (power, remote controller, transmission cables) above the ceil-
ing may be bitten by mice. Use as many metal pipes as possible to insert the
cables into them for protection.
10
Air filter (supplied at site)
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 Suniso 4GS or 3GS (small amount) refrigerator oil to coat the flare
and flange connection part. (For models using R22)
• Use ester oil, ether oil or alkylbenzene (small amount) as the refrigera-
tor oil to coat flares and flange connections. (For models using R410A)
- 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.
(A)
2. Ensure that any cross-wise drain piping is less than 20 m [65 ft] (excluding
the difference 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 [1-
9/32 in]) for drain piping.
4. Ensure that collected pipes are 10 cm [3-15/16 in] lower than the unit body's
drain port as shown in B.
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 gen-
erated.
[Fig. 7.2.1] (P. 4)
Downward slope 1/100 or more
Drain hose (Accessory)
Indoor unit
Collective piping
Maximize this length to approx. 10 cm [3-15/16 in]
8. When 2 drains are necessary, attach the drain hose to the adjacent drain pip-
ing not in use.
9. When the drain piping connection is one place, please do not use the drain
piping closed with the rubber cork.
Access door
Ensure sufficient length to prevent short cycling
Air outlet
Keep duct-work length 850 [33-15/32 in] or more
Caution:
Inlet duct is 850 mm [33-15/32 in] or more necessary to construct.
Always install horizontal.
6. Never connect the power cable to leads for the transmission cables. Other-
wise, the units would be broken.
7. Be sure to connect control cables to the indoor unit, remote controller, and
the outdoor unit.
8. Select control cables from the conditions given in page 11.
Caution:
Be sure to ground the indoor unit. Do not connect the grounding cable to
any gas pipe, water pipe, lightening rod, or telephone earth cable. Incom-
plete grounding may cause a risk of electric shock.
Ceiling