Request For Refrigerant Piping Connection; Connecting Refrigerant Pipes And Drain Pipes; Refrigerant Piping Work; Drain Piping Work - Mitsubishi Electric CITY MULTI PDFY-P20VM-E Installation Manual

6.3. Request for refrigerant piping connection

Description of parts to be used
No. Work procedures
Mount the provided pipe insula-
tion (1) on the liquid pipe of the
refrigerant piping, and then mount
the flare insulation (2) on the gas
pipe.
1
Fixing of insulated pipe
2
Fixing of flare insulation
3
[Fig. 6.3.1] (P.3)
A "0-0 gas" mark
C "OUTER" mark
E Refrigerant piping (gas)
G Field refrigerant piping
I Insulation material
K Pull in this direction.
M Flare nut
O Move to the original position.
[Fig. 6.3.2] (P.3)
(figure showing the flare insulation)
A Field refrigerant piping
C Unit body plate
E INNER
G Provided flare insulation (2)

7. Connecting refrigerant pipes and drain pipes

7.1. Refrigerant piping work

This piping work must be done in accordance with the installation manuals for both
outdoor unit and BC controller (simultaneous cooling and heating series R2).
• Series R2 is designed to operate in a system that the refrigerant pipe from an
outdoor unit is received by BC controller and branches at the BC controller to
connect between indoor units.
• For constraints on pipe length and allowable difference of elevation, refer to
the outdoor unit manual.
• The method of pipe connection is flare connection.
Cautions on refrigerant piping
s s s s s Be sure to use non-oxidative brazing for brazing to ensure that no for-
eign matter or moisture enter into the pipe.
s s s s s Be sure to apply refrigerating machine oil over the flare connection seat-
ing surface and tighten the connection using a double spanner.
s s s s s Provide a metal brace to support the refrigerant pipe so that no load is
imparted to the indoor unit end pipe. This metal brace should be pro-
vided 50 cm away from the indoor unit's flare connection.
Warning:
When installing and moving the unit, do not charge it with refrigerant other
than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to mal-
function and result in severe damage.
Caution:
• Use refrigerant piping made of C1220 (Cu-DHP) phosphorus deoxidized
copper as specified in the JIS H3300 "Copper and copper alloy seamless
pipes and tubes". In addition, be sure that the inner and outer surfaces of
the pipes are clean and free of hazardous sulphur, oxides, dust/dirt, shav-
ing particles, oils, moisture, or any other contaminant.
• Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerator oil
in the existing piping will cause the new refrigerant to deteriorate.
Detail of work
"INNER" and "OUTER" are marked on the in-
side of the flare insulation. Mount the portion
marked "INNER" near the unit body and the
portion marked "OUTER" on the field piping
side.
• Fasten the insulated pipe with the insula-
tion tape.
• Firmly secure the insulation with the pro-
vided tie band (4) at the position indicated
on the drawing.
• Fasten the flare insulation with the provided
tape (3).
• Fasten with the provided tie band (4) at the
position indicated on the drawing.
B "INNER" mark
D Flare insulation (2)
F Refrigerant piping (liquid)
H Pipe insulation (1)
J Flare nut
L Insulation material
N There must be no gap.
B There must be no gap.
D OUTER
F Unit body
Item to be observed
• Using the flare insulation of a different model may
result in condensation forming. Check the model
name on the insulation and be sure to use the cor-
rect one.
• To prevent a gap from forming near the unit's side
plate, be sure that the flare insulation firmly con-
tacts the unit's side plate before mounting.
• Incorrectly mounting the "INNER" and "OUTER"
sides of the insulation may result in condensation
forming.
Seal the slit securely so that there are no openings.
Be sure to mount the insulation so that the slit is on
the top.
Seal the slit securely so that there are no openings.
Be sure to mount the insulation so that the slit is on
the top.
[Fig. 6.3.3] (P.3)
A Tape (2)
C Provided tie band (4)
Notes:
*1 Insert the flare nut into the field refrigerant piping. Pull the insulation
material back at the area where it will be flared, then return it to its
original position after performing the flare work.
Exposing copper piping may result in condensation forming. Be ex-
tremely careful when performing this operation.
*2 There must be no gap.
*3, *4 There must be no gap. Slit should be on the top.
• Store the piping to be used during installation indoors and keep both
ends of the piping sealed until just before brazing.
- If dust, dirt, or water gets into the refrigerant cycle, the oil will deteriorate and
the compressor may fail.
• Use Suniso 4GS or 3GS (small amount) refrigerator oil to coat the flare
and flange connection part. (For models using R22)
• Use ester oil, ether oil or alkylbenzene (small amount) as the refrigerator
oil to coat flares and flange connections. (For models using R410A or
R407C)
- The refrigerant used in the unit is highly hygroscopic and mixes with water
and will degrade the refrigerator oil.

7.2. Drain piping work

1. Ensure that the drain piping is downward (pitch of more than 1/100) to the
outdoor (discharge) side. Do not provide any trap or irregularity on the way.
(1)
2. Ensure that any cross-wise drain piping is less than 20 m (excluding the differ-
ence of elevation). If the drain piping is long, provide metal braces to prevent it
from waving. Never provide any air vent pipe. Otherwise drain may be ejected.
3. Use a hard vinyl chloride pipe VP-25 (with an external diameter of 32 mm) for
drain piping.
4. Ensure that collected pipes are 10 cm lower than the unit body's drain port as
shown in 2.
5. Do not provide any odor trap at the drain discharge port.
6. Put the end of the drain piping in a position where no odor is generated.
7. Do not put the end of the drain piping in any drain where ionic gases are
generated.
[Fig. 7.2.1] (P.4)
A Downward slope 1/100 or more
C Indoor unit
E Maximize this length to approx. 10 cm
• Use the following instructions when using an optional drain-up
mechanism.
Reference drawing
Fig. 6.3.1 (P.3)
Fig. 6.3.2 (P.3)
(Note *2)
Fig. 6.3.2 (P.3)
Fig. 6.3.3 (P.3)
(Note *3)
Fig. 6.3.3 (P.3)
(Note *4)
B Fasten with tape.
B Drain hose (Accessory)
D Collective piping
9