Safety Precaution - Mitsubishi Electric MXZ-2C20NA2 Service Manual

2

SAFETY PRECAUTION

2-1. ALWAYS OBSERVE FOR SAFETY
Before obtaining access to terminal, all supply circuit must be disconnected.
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.
2-2. CAUTIONS RELATED TO R410A REFRIGERANT
Cautions for units utilizing refrigerant R410A
Make sure that the inside and outside of refriger-
ant 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.
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 deteri-
oration 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.
Do not use refrigerant other than R410A.
If other refrigerant (R22, etc.) is used, chlorine in refrigerant
can cause deterioration of refrigerant oil, etc.
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.
OBH702N
Precautions during the repair service
• Do not perform the work involving the electric parts with
wet hands.
• Do not pour water into 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 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.
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.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refriger-
ant 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.
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Flare tool
Size adjustment gauge
Vacuum pump adaptor
Electronic refrigerant
charging scale