Refrigerant Piping Work; Restrictions - Mitsubishi Electric City Multi PUHY-P-YKB-A1 series Installationshandbuch

9. Refrigerant piping work

Do not use any refrigerant other than the type indicated in the manuals for the unit and on
the nameplate.
- Doing so will cause the unit or pipes to burst, or result in an explosion or fire during use, during
repairs, or at the time of disposal of the unit.
- It may also be in violation of applicable laws.
- MITSUBISHI ELECTRIC CORPORATION cannot be held responsible for malfunctions or
accidents resulting from the use of the wrong type of refrigerant.
After the installation has been completed, check for refrigerant leaks.
- If the refrigerant leaks, oxygen starvation may result. If the leaked refrigerant comes in contact
with a heat source, toxic gas will be generated.
Use the following tools specifically designed for use with the specified refrigerant: Gauge
manifold, charge hose, gas leak detector, check valve, refrigerant charge base, vacuum
gauge, and refrigerant recovery equipment.
- Gas leak detectors for conventional refrigerants will not react to a refrigerant that does not
contain chlorine.
- If the specified refrigerant is mixed with water, refrigerant oil, or another refrigerant, the
refrigerant oil will deteriorate and the compressor will malfunction.
Do not use existing refrigerant piping.
- The old refrigerant and refrigerant oil in the existing piping contain a large amount of chlorine,
which will cause the refrigerant oil in the new unit to deteriorate and cause the compressor to
malfunction.

9-1. Restrictions

・Existing refrigerant piping must not be used because the design pressure for systems using R410A is higher than
that for systems using other types of refrigerants.
・Do not install outdoor unit piping when it is raining.
・Do not use special detergents for washing piping.
・Always observe the restrictions on refrigerant piping (such as pipe size, pipe length, and vertical separation
distance) to prevent equipment failure or a decline in heating/cooling performance.
・Do not install solenoid valves to prevent oil backflow and compressor start-up failure.
・Do not install a sight glass because it may show improper refrigerant flow. If a sight glass is installed, inexperienced
technicians that use the glass may overcharge the refrigerant.
・Branching cannot be made after header branching.
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KD79S703H01
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GB-17
From outdoor unit
Cap
Indoor unit