To Connect The Refrigerant Piping To The Outdoor Unit; Checking The Refrigerant Piping; About Checking The Refrigerant Piping; Precautions When Checking The Refrigerant Piping - Daikin RXM20R5V1B Installer's Reference Manual

▪ When it is expected that the operating pressure will be low (e.g.
when cooling will be performed while the outside air temperature
is low), sufficiently seal the flare nut in the stop valve on the gas
line with silicon sealant to prevent freezing.
Silicon sealant, make sure there is no gap.
To open/close the stop valve
1 Remove the stop valve cover.
2 Insert a hexagon wrench (liquid side: 4 mm, gas side: 6 mm)
into the valve stem and turn the valve stem:
Counterclockwise to open
Clockwise to close
3 When the stop valve CANNOT be turned any further, stop
turning.
4 Install the stop valve cover.
Result: The valve is now open/closed.
To handle the stem cap
▪ The stem cap is sealed where indicated with the arrow. Do NOT
damage it.
▪ After handling the stop valve, tighten the stem cap, and check for
refrigerant leaks.
Item
Stem cap, liquid side
Stem cap, gas side
To handle the service cap
▪ ALWAYS use a charge hose equipped with a valve depressor pin,
since the service port is a Schrader type valve.
▪ After handling the service port, tighten the service port cap, and
check for refrigerant leaks.
Item
Service port cap
6.4.7 To connect the refrigerant piping to the
outdoor unit
▪ Piping length. Keep field piping as short as possible.
▪ Piping protection. Protect the field piping against physical
damage.
1 Connect the liquid refrigerant connection from the indoor unit to
the liquid stop valve of the outdoor unit.
ARXM25+35R5V1B RXM20~35R5V1B
R32 Split Series
4P519439-8H – 2020.07
Tightening torque (N∙m)
14.2~17.2
17.1~20.9
Tightening torque (N∙m)
10.8~14.7
a
c b
a Liquid stop valve
b Gas stop valve
c Service port
2 Connect the gas refrigerant connection from the indoor unit to
the gas stop valve of the outdoor unit.
NOTICE
It is recommended that the refrigerant piping between
indoor and outdoor unit is installed in a ducting or the
refrigerant piping is wrapped with finishing tape.
6.5

Checking the refrigerant piping

6.5.1

About checking the refrigerant piping

The outdoor unit's internal refrigerant piping has been factory tested
for leaks. You only have to check the outdoor unit's external
refrigerant piping.
Before checking the refrigerant piping
Make sure the refrigerant piping is connected between the outdoor
unit and the indoor unit.
Typical workflow
Checking the refrigerant piping typically consists of the following
stages:
1 Checking for leaks in the refrigerant piping.
2 Performing vacuum drying to remove all moisture, air or
nitrogen from the refrigerant piping.
If there is a possibility of moisture being present in the refrigerant
piping (for example, water may have entered the piping), first carry
out the vacuum drying procedure below until all moisture has been
removed.
6.5.2 Precautions when checking the
refrigerant piping
INFORMATION
Also read the precautions and requirements in the
following chapters:
▪ General safety precautions
▪ Preparation
NOTICE
Use a 2-stage vacuum pump with a non-return valve that
can evacuate to a gauge pressure of −⁠ 1 00.7 kPa
(−⁠ 1 .007 bar)(5 Torr absolute). Make sure the pump oil
does not flow oppositely into the system while the pump is
not working.
NOTICE
Use this vacuum pump for R32 exclusively. Using the
same pump for other refrigerants may damage the pump
and the unit.
NOTICE
▪ Connect the vacuum pump to the service port of the
gas stop valve.
▪ Make sure that the gas stop valve and liquid stop valve
are firmly closed before performing the leak test or
vacuum drying.
6 Installation
Installer reference guide
15