Refrigerant Piping - McQuay M5WMY10KR Installation Manual

01_EN_3P257187-1A.fm Page 11 Thursday, November 12, 2009 12:01 PM
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 flare nut avoid
tightening with over 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 0.045 kcal/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
O.D. 9.5mm
Minimum bend radius
Thickness 0.8mm (C1220T-O)
3) Use separate thermal insulation pipes for gas and liquid refrigerant pipes.
■English
[Apply oil]
Do not apply refrigeration
oil to the outer surface.
Flare nut
Flare nut tightening torque
Gas side
3/8 inch
32.7-39.9N m
(330-407kgf cm)
Liquid side
O.D. 6.4mm
30mm or more
Apply refrigeration oil to
Torque wrench
the inner surface of the
flare.
Spanner
Piping union
Liquid side
1/4 inch
14.2-17.2N m
(144-175kgf cm)
Rain
Gas pipe thermal Liquid pipe thermal
insulation
I.D. 12-15mm I.D. 8-10mm
Thickness 10mm Min.
[Tighten]
Flare nut
Be sure to
place a cap.
If no flare cap is
available, cover
the flare mouth
with tape to keep
dirt or water out.
Inter-unit wiring
Gas pipe
Liquid pipe
Gas pipe
Liquid pipe
insulation
insulation
Finishing tape
Drain hose
insulation
Wall
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