Precautions For Devices That Use R410A Refrigerant; Before Installation; Before Installation (Relocation) - Electrical Work; Before Starting The Test Run - Mitsubishi Electric City Multi PUHY-P-THMU-A Installation Manual

Air-conditioners for building application
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1.2. Precautions for devices that use R410A
refrigerant
Caution:
Do not use existing refrigerant piping.
- The old refrigerant and refrigerant oil in the existing piping contains a large
amount of chlorine which may cause the refrigerant oil of the new unit to
deteriorate.
- R410A is a high-pressure refrigerant and can cause the existing piping to
burst.
Use refrigerant piping made of phosphorus deoxidized copper and cop-
per 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 contami-
nant.
- Contaminants on the inside of the refrigerant piping may cause the refriger-
ant oil to deteriorate.
Store the piping to be used during installation indoors and keep both
ends of the piping sealed until just before brazing. (Store elbows and
other joints in a plastic bag.)
- If dust, dirt, or water enters the refrigerant cycle, deterioration of the oil and
compressor failure may result.
Apply only a small amount of ester oil, ether oil, or alkyl benzene to flare
connections (for indoor unit).
- Infiltration of a large amount of mineral oil may cause the refrigerant oil to
deteriorate.
Use liquid refrigerant to fill the system.
- If gas refrigerant is used to fill the system, the composition of the refrigerant
in the cylinder will change and performance may drop.
Do not use a refrigerant other than R410A.
- If another refrigerant (R22, etc.) is mixed with R410A, the chlorine in the
refrigerant may cause the refrigerant oil to deteriorate.
Use a vacuum pump with a reverse flow check valve.
- The vacuum pump oil may flow back into the refrigerant cycle and cause the
refrigerant oil to deteriorate.
Do not use the following tools that are used with conventional refriger-
ants.
(Gauge manifold, charge hose, gas leak detector, reverse flow check valve,
refrigerant charge base, refrigerant recovery equipment)
- If the conventional refrigerant and refrigerant oil are mixed in the R410A, the
refrigerant may deteriorate.
- If water is mixed in the R410A, the refrigerant oil may deteriorate.
- Since R410A does not contain any chlorine, gas leak detectors for conven-
tional refrigerants will not react to it.
Do not use a charging cylinder.
- Using a charging cylinder may cause the refrigerant to deteriorate.
Be especially careful when managing the tools.
- If dust, dirt, or water gets into the refrigerant cycle, the refrigerant may dete-
riorate.

1.3. Before installation

Caution:
Do not install the unit where combustible gas may leak.
- If the gas leaks and accumulates around the unit, an explosion may result.
Do not use the air conditioner where food, pets, plants, precision instru-
ments, or artwork are kept.
- The quality of the food, etc. may deteriorate.
Do not use the air conditioner in special environments.
- Oil, steam, sulfuric smoke, etc. can significantly reduce the performance of
the air conditioner or damage its parts.
When installing the unit in a hospital, communication station, or similar
place, provide sufficient protection against noise.
- Inverter equipment, private power generator, high-frequency medical equip-
ment, or radio communication equipment may cause the air conditioner to
operate erroneously, or fail to operate. On the other hand, the air conditioner
may affect such equipment by creating noise that disturbs medical treatment
or image broadcasting.
Do not install the unit on or over things that are subject to water damage.
- When the room humidity exceeds 80% or when the drain pipe is clogged,
condensation may drip from the indoor unit. Perform collective drainage work
together with the outdoor unit, as required.

2. About the product

This unit uses R410A-type refrigerant
Piping for systems using R410A may be different from that for systems using
conventional refrigerant because the design pressure in systems using R410A
is higher. Refer to the Data Book for more information.
Some of the tools and equipment used for installation with systems that use
other types of refrigerant cannot be used with the systems using R410A. Refer
to the Data Book for more information.
1.4. Before installation (relocation) - electri-
cal work
Caution:
Ground the unit.
- Do not connect the ground wire to gas or water pipes, lightning rods, or
telephone ground lines. Improper grounding may result in electric shock.
Install the power cable so that tension is not applied to the cable.
- Tension may cause the cable to break and generate heat and cause a fire.
Install a leak circuit breaker, as required.
- If a leak circuit breaker is not installed, electric shock may result.
Use power line cables of sufficient current carrying capacity and rating.
- Cables that are too small may leak, generate heat, and cause a fire.
Use only a circuit breaker and fuse of the specified capacity.
- A fuse or circuit breaker of a larger capacity, or the use of a substitute simple
steel or copper wire may result in a general unit failure or fire.
Do not wash the air conditioner units.
- Washing them may cause an electric shock.
Be careful that the installation base is not damaged by long use.
- If the damage is left uncorrected, the unit may fall and cause personal injury
or property damage.
Install the drain piping according to this Installation Manual to ensure
proper drainage. Wrap thermal insulation around the pipes to prevent
condensation.
- Improper drain piping may cause water leakage causing damage to furniture
and other possessions.
Be very careful about transporting the product.
- One person should not carry the product. Its weight is in excess of 20 kg
[45LBS].
- Some products use PP bands for packaging. Do not use any PP bands as a
means of transportation. It is dangerous.
- Do not touch the heat exchanger fins. Doing so may cut your fingers.
- When transporting the outdoor unit, support it at the specified positions on
the unit base. Also support the outdoor unit at four points so that it cannot
slip sideways.
Safely dispose of the packing materials.
- Packing materials, such as nails and other metal or wooden parts, may cause
stabs or other injuries.
- Tear apart and throw away plastic packaging bags so that children will not
play with them. If children play with a plastic bag which has not been torn
apart, they face the risk of suffocation.

1.5. Before starting the test run

Caution:
Turn on the power at least 12 hours before starting operation.
- Starting operation immediately after turning on the main power switch can
result in irreversible damage to internal parts. Keep the power switch turned
on during the operational season. Make sure of the phase order of power
supply and voltage between each phase.
Do not touch the switches with wet fingers.
- Touching a switch with wet fingers can result in an electric shock.
Do not touch the refrigerant pipes during and immediately after opera-
tion.
- During and immediately after operation, the refrigerant pipes may be hot or
cold, depending on the condition of the refrigerant flowing through the refrig-
erant piping, compressor, and other refrigerant cycle parts. Your hands may
suffer burns or frostbite if you touch the refrigerant pipes.
Do not operate the air conditioner with the panels and guards removed.
- Rotating, hot, or high-voltage parts can cause injuries.
Do not turn off the power immediately after stopping operation.
- Always wait at least 5 minutes before turning off the power. Otherwise,
drainage water leakage or mechanical failure of sensitive parts may occur.
Do not touch the surface of the compressor during servicing.
- If the unit is connected to a supply and not running, the crank case heater
located at the base of the compressor may still be operating.
Do not use the existing piping, as it contains chlorine, which is found in con-
ventional refrigerating machine oil and refrigerant. This chlorine will deteriorate
the refrigerant machine oil in the new equipment. The existing piping must not
be used as the design pressure in systems using R410A is higher than that in
the systems using other types of refrigerant and the existing pipes may burst.
3

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