18 | Piping installation
Installer and user reference guide
94
RXMLQ8 + RXYLQ10~14T7Y1B*
VRV IV system air conditioner
4P543427-1A – 2020.10
▪ Reinforce the insulation on the refrigerant piping according to the installation
environment.
Ambient temperature Humidity Minimum thickness
≤30°C 75% to 80% RH 15mm
>30°C ≥80% RH 20mm
▪ If there is a possibility that condensation on the stop valve might drip down into
the indoor unit through gaps in the insulation and piping because the outdoor
unit is located higher than the indoor unit, this must be prevented by sealing up
the connections. See below figure.
a Insulation material
b Caulking etc.
18.4 Charging refrigerant
18.4.1 Precautions when charging refrigerant
WARNING
▪ ONLY use R410A as refrigerant. Other substances may cause explosions and
accidents.
▪ R410A contains fluorinated greenhouse gases. Its global warming potential (GWP)
value is 2087.5. Do NOT vent these gases into the atmosphere.
▪ When charging refrigerant, ALWAYS use protective gloves and safety glasses.
NOTICE
If the power of some units is turned off, the charging procedure cannot be finished
properly.
NOTICE
In case of a multiple outdoor system, turn on the power of all outdoor units.
NOTICE
Be sure to turn ON the power 6 hours before operation in order to have power
running to the crankcase heater and to protect the compressor.
NOTICE
If operation is performed within 12 minutes after the indoor and outdoor units are
powered on, the compressor will not operate before the communication is
established in a correct way between outdoor unit(s) and indoor units.
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