Refrigerant Piping - Daikin FTXG20LV1BW Installation Manual

01_EN_3P358178-1A.fm Page 7 Monday, December 16, 2013 3:59 PM
Refrigerant Piping Work
2.

Refrigerant piping

CAUTION
• Use the flare nut fixed to the main unit. (To prevent cracking of the flare nut by aged deterioration.)
• To prevent gas leakage, apply refrigeration oil only to the inner surface of the flare. (Use refrigeration oil for R410A.)
• Use torque wrenches when tightening the flare nuts to prevent damage to the flare nuts and gas leakage.
Align the centres of both flares and tighten the flare nuts 3 or 4 turns by hand. Then tighten them fully with the torque wrenches.
Do not apply refrigeration
oil to the outer surface.
Flare nut
Do not apply refrigeration oil to
the flare nut to avoid tightening
with excessive torque.
2-1. Caution on piping handling
1) Protect the open end of the pipe against dust and moisture.
2) All pipe bends should be as gentle as possible. Use a pipe bender
for bending.
2-2. Selection of copper and heat insulation materials
When using commercial copper pipes and fittings, observe the following:
1) Insulation material: Polyethylene foam
Heat transfer rate: 0.041 to 0.052W/mK (0.035 to 0.045kcal/mh°C)
Refrigerant gas pipe's surface temperature reaches 110°C max.
Choose heat insulation materials that will withstand this temperature.
2) Be sure to insulate both the gas and liquid piping and to provide insulation
dimensions as below.
Gas side
25/35 class
O.D. 9.5mm
30mm or more
Thickness 0.8mm (C1220T-O)
3) Use separate thermal insulation for gas and liquid refrigerant pipes.
7
[Apply oil]
Apply refrigeration
oil to the inner
surface of the flare.
Flare nut tightening torque
Gas side
3/8 inch 1/2 inch
32.7-39.9N•m 49.5-60.3N•m
(330-407kgf•cm) (505-615kgf•cm)
Liquid side
50 class
O.D. 6.4mm
O.D. 12.7mm
Minimum bend radius
40mm or more 30mm or more
[Tighten]
Torque wrench
Spanner
Piping union
Flare nut
Liquid side
1/4 inch
14.2-17.2N•m
(144-175kgf•cm)
Be sure to
place a cap.
Rain
If no flare cap is
available, cover the
flare mouth with
tape to keep dirt or
water out.
Gas pipe
Gas pipe
insulation
Finishing tape
Gas pipe thermal insulation
25/35 class 50 class
I.D. 12-15mm I.D. 14-16mm
Thickness 10mm Min.
Wall
Inter-unit wire
Liquid pipe
Liquid pipe
insulation
Drain hose
Liquid pipe
thermal insulation
I.D. 8-10mm
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