Safety Precaution - Mitsubishi Electric PUMY-P250YBM2-ER Technical & Service Manual

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SAFETY PRECAUTION

1-1. CAUTIONS RELATED TO NEW REFRIGERANT
Cautions for units utilizing refrigerant R410A
Preparation before the repair service
• Prepare the proper tools.
• Prepare the proper protectors.
• Provide adequate ventilation.
• After stopping the operation of the air conditioner, turn
off the power-supply breaker.
• Discharge the condenser before the work involving the
electric parts.
Use new refrigerant pipes.
Avoid using thin pipes.
Make sure that the inside and outside of refrige-
rant piping is clean and it has no contaminants
such as sulfur, oxides, dirt, shaving particles, etc.,
which are hazard to refrigerant cycle.
In addition, use pipes with specified thickness.
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil, etc.
Follow the instructions below to prevent abrasive
components contained in sandpaper and cutting tools
from entering the refrigerant circuit because those
components can cause failures of the compressor
and valves.
• To deburr pipes, use a reamer or other deburring tools,
not sandpaper.
• To cut pipes, use a pipe cutter, not a grinder or other
tools that use abrasive materials.
• When cutting or deburring pipes, do not allow cutting
chips or other foreign matters to enter the pipes.
• If cutting chips or other foreign matters enter pipes, wipe
them off the inside of the pipes.
Store the piping indoors, and keep both ends of the
piping sealed until just before brazing.
(Leave elbow joints, etc. in their packaging.)
If dirt, dust or moisture enters into refrigerant cycle, that
can cause deterioration of refrigerant oil or malfunction of
compressor.
The refrigerant oil applied to flare and flange
connections must be ester oil, ether oil or
alkylbenzene oil in a small amount.
If large amount of mineral oil enters, that can cause
deterioration of refrigerant oil, etc.
Charge refrigerant from liquid phase of gas
cylinder.
If the refrigerant is charged from gas phase, composition
change may occur in refrigerant and the efficiency will be
lowered.
TCH091
Precautions during the repair service
• Do not perform the work involving the electric parts
with wet hands.
• Do not pour water into the electric parts.
• Do not touch the refrigerant.
• Do not touch the hot or cold areas in the refrigerating cycle.
• When the repair or the inspection of the circuit needs
to be done without turning off the power, exercise great
caution not to touch the live parts.
• When opening or closing the valve below freezing
temperatures, refrigerant may spurt out from the gap
between the valve stem and the valve body, resulting in
injuries.
Use a vacuum pump with a reverse flow check
valve.
Vacuum pump oil may flow back into refrigerant cycle and
that can cause deterioration of refrigerant oil, etc.
Use the following tools specifically designed for
use with R410A refrigerant.
The following tools are necessary to use R410A
refrigerant.
Tools for R410A
Gauge manifold
Charge hose
Gas leak detector
Torque wrench
Handle tools with care.
If dirt, dust or moisture enters into refrigerant cycle, that
can cause deterioration of refrigerant oil or malfunction of
compressor.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refrigera-
nt will change and the efficiency will be lowered.
Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.
Use the specified refrigerant only.
Never use any refrigerant other than that specified.
Doing so may cause a burst, an explosion, or fire when
the unit is being used, serviced, or disposed of.
Correct refrigerant is specified in the manuals and on the
spec labels provided with our products.
We will not be held responsible for mechanical failure,
system malfunction, unit breakdown or accidents caused
by failure to follow the instructions.
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Flare tool
Size adjustment gauge
Vacuum pump adaptor
Electronic refrigerant
charging scale