Daikin Super Multi NX 3MXS-G Series Engineering Data page 304

EDUS121131
4
Purging Air and Checking Gas Leakage
● When piping work is completed, it is necessary to purge the air and check for gas leakage.
WARNING
1) Do not mix any substance other than the specified refrigerant (R410A) into the refrigeration cycle.
2) When refrigerant gas leaks occur, ventilate the room as soon and as much as possible.
3) R410A, as well as other refrigerants, should always be recovered and never be released directly into the environment.
4) Use a vacuum pump for R410A exclusively. Using the same vacuum pump for different refrigerants may damage
the vacuum pump or the unit.
● If using additional refrigerant, perform air purging from the refrigerant pipes and indoor unit using a vacuum pump, then
charge additional refrigerant.
● Use a hexagonal wrench (3/16") to operate the stop valve rod.
● All refrigerant pipe joints should be tightened with a torque wrench at the specified tightening torque.
1) Connect projection side of charging hose (which comes from gauge manifold) to gas stop valve's service port.
2) Fully open gauge manifold's low-pressure valve (Lo) and completely close its high-pressure valve (Hi).
(High-pressure valve subsequently requires no operation.)
3) Apply vacuum pumping. Check that the compound pressure gauge reads –29.9in Hg.
Evacuation for at least 1 hour is recommended.
4) Close gauge manifold's low-pressure valve (Lo) and stop vacuum pump.
(Leave as is for 4-5 minutes and make sure the coupling meter needle does not go back.
If it does go back, this may indicate the presence of moisture or leaking from connecting parts. After inspecting all
the connection and loosening then retightening the nuts, repeat steps 2-4.)
5) Remove covers from liquid stop value and gas stop valve.
6) Turn the liquid stop valve's rod 90 degrees counterclockwise with a hexagonal wrench to open valve.
Close it after 5 seconds, and check for gas leakage.
Using soapy water, check for gas leakage from indoor unit's flare and outdoor unit's flare and valve rods.
After the check is complete, wipe all soapy water off.
7) Disconnect charging hose from gas stop valve's service port, then fully open liquid and gas stop valves.
(Do not attempt to turn valve rod beyond its stop.)
8) Tighten valve caps and service port caps for the liquid and gas stop valves with a torque wrench at the specified
torques. See "3 Refrigerant Piping" in "Refrigerant Piping Work (1)" for details.
5
Refilling The Refrigerant
Check the type of refrigerant to be used on the machine nameplate.
Precautions when adding R410A
Fill from the liquid pipe in liquid form.
It is a mixed refrigerant, so adding it in gas form may cause the refrigerant composition to change, preventing normal operation.
1) Before filling, check whether the cylinder has a siphon attached or not. (It should have something like "liquid filling
siphon attached" displayed on it.)
Filling a cylinder with an attached siphon
Stand the cylinder upright when filling.
There is a siphon pipe inside, so the
cylinder need not be upside-down to
fill with liquid.
2) Be sure to use the R410A tools to ensure pressure and to prevent foreign objects entering.
Installation Manual
Refrigerant Piping Work (2)
Filling other cylinders
Turn the cylinder upside-down
when filling.
Outdoor Unit
2
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