17
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Piping installation
Installer and user reference guide
89
R R8T7V1B
VRV IV heat pump for indoor installation
4P499898-1A – 2020.10
INFORMATION
After opening the stop valve, it is possible that the pressure in the refrigerant piping
does NOT increase. This might be caused by e.g. the closed state of the expansion
valve in the compressor unit circuit, but does NOT present any problem for correct
operation of the unit.
17.3.6 To insulate the refrigerant piping
After finishing the leak test and vacuum drying, the piping must be insulated. Take
into account the following points:
▪
Make sure to insulate the connection piping and refrigerant branch kits entirely.
▪
Be sure to insulate the liquid and gas piping (for all units).
▪
Use heat resistant polyethylene foam which can withstand a temperature of 70°C
for liquid piping and polyethylene foam which can withstand a temperature of
120°C for gas piping.
▪
Reinforce the insulation on the refrigerant piping according to the installation
environment.
Ambient temperature
Humidity
Minimum thickness
≤30°C
75% to 80% RH
15 mm
>30°C
≥80% RH
20 mm
▪
If there is a possibility that condensation on the stop valve might drip down into
the indoor unit or into the heat exchanger unit through gaps in the insulation and
piping because the compressor unit is located higher than the indoor unit or
higher than the heat exchanger unit, this must be prevented by sealing up the
connections. See below figure.
a
b
a
Insulation material
b
Caulking etc.
17.4 Charging refrigerant
17.4.1 About charging refrigerant
The compressor unit is factory charged with refrigerant, but depending on the field
piping you have to charge additional refrigerant.
Before charging refrigerant
Make sure the compressor unit's
external
refrigerant piping is checked (leak test,
vacuum drying).
