Specifications

EDUS39-600-F20_b
FXOQ-M 26
Installation
Step 5: REFRIGERANT PIPING WORK
1. This section shows the piping method between the outdoor unit, the Electronic Expansion Valve unit, and the Vertical Air
Handling unit. Select the pipe size and refrigerant branch kit depending on how the piping will be laid.
2. For refrigerant piping of outdoor units, see the installation manual attached to the outdoor unit.
3. Execute heat insulation work completely on both sides of the gas piping and the liquid piping. Otherwise a water leakage can
result.
4. Before refrigerant piping work, check if the type of refrigerant is R410A. If not, proper operation is not possible.
5. Improve the insulation on the refrigerant piping depending on the installation environment. If the insulation is not sufficient,
condensate may form on the surface of the insulation.
NOTE
6. The temperature of the gas piping can reach up to approximately 220
0
F so use insulation that is sufficiently resistant.
• Use a pipe cutter and flare substitute for the type for the type of R-410A.
• Apply ester oil or ether around the flare section before connecting.
• To prevent dust, moisture, or other foreign matter from infiltrating the tube, either pinch the end or cover it with tape.
• Do not allow anything other than the designated refrigerant to get mixed into t he refrigerant circuit, such as air. If any refrig-
erant gas leaks while working on the unit, immediately ventilate the room thoroughly.
• Use the flare nuts attached to the main body.
• Ensure the outdoor unit is charged with refrigerant.
• For the refrigerant piping and branching, follow the Pipe Connection Procedure.
• Be sure to use both a spanner and torque wrench, as shown in Figure 10, when
connection or disconnecting piping to/from unit.
• Refer to Table 1 for the dimensions of flare nut spaces.
• When connecting the flare nut, coat the flare both inside and outside with ester
or ether oil and initially tighten 3 or 4 turns by hand before tightening firmly. See
Figure 11.
• Refer to Table 1 to determine the proper tightening torque.
• Over-tightening may damage the flare and cause a refrigerant leakage.
• You must use a torque wrench but if one is not available, you may follow the
instructions in Table 2.
• When you continue tightening the flare nut with a spanner, there is a point
where the tightening torque suddenly increases. From that position, further
tighten the flare nut to the angle shown in Table 2.
CAUTION
After piping work is completed, make sure that there is no gas leak.
• Do not use anti-oxidants when brazing the piping joints as residue can clog piping and break equipment.
• Do not use flux when brazing refrigerant piping. Use the phosphor copper brazing filler metal (BCuP-2: JISz3264/B-Cu93P-
710/795: ISO 3677) which does not require flux. Flux has an extremely negative effect on refrigerant piping systems and if
chlorine-based flux is used, it causes pipe corrosion. Flux
containing fluorine damages refrigerant oil.
• Do not use anti-oxidants when brazing the piping joints as
residue can clog piping and break equipment.
• Piping is very hot after brazing so use caution to avoid
burns.
• Before brazing local refrigerant piping, nitrogen gas must
be blown through the piping to expel air from pipes.
• If your brazing is done without nitrogen gas blowing, a
large amount of oxide film develops inside the piping and
could cause system malfunction. Once this is done, con
-
nect the indoor unit with a flared connection.
• Nitrogen should be set to 2.90 PSI with a pressure-reduc-
ing valve if brazing while inserting nitrogen into the piping.
• Do not use anti-oxidants when brazing the piping joints.
Residue can clog piping and break equipment.