Sanyo R410A operation manual Tube diameter Tightening torque Tube thickness Approximate

Caution Before Connecting Tubes Tightly

(1)Apply a sealing cap or water-proof tape to prevent dust or water from entering the tubes before they are used.

(2)Be sure to apply refrigerant lubricant to the match- ing surfaces of the flare and union before connect- ing them together. This is effective for reducing gas leaks. (Fig. 5-4)

(3)For proper connection, align the union tube and flare tube straight with each other, then screw in the flare nut lightly at first to obtain a smooth match. (Fig. 5-5)

●Adjust the shape of the narrow tube (liquid tube) using a tube bender at the installation site and connect it to the narrow tubing side (liquid tubing side) valve using a flare.

Cautions During Brazing

●Replace air inside the tube with nitrogen gas to prevent copper oxide film from forming during the brazing process. (Oxygen, carbon dioxide and Freon are not acceptable.)

●Do not allow the tubing to get too hot during brazing. The nitrogen gas inside the tubing may overheat, causing refrigerant system valves to become damaged. Therefore allow the tubing to cool when brazing.

●Use a reducing valve for the nitrogen cylinder.

●Do not use agents intended to prevent the for- mation of oxide film. These agents adversely affect the refrigerant and refrigerant oil, and may cause damage or malfunctions.

5-2. Connecting Tubing Between Indoor and Out- door Units

(1)Tightly connect the indoor-side refrigerant tubing extended from the wall with the outdoor-side tub- ing.

(2)To fasten the flare nuts, apply specified torque as at right:

●When removing the flare nuts from the tubing con- nections, or when tightening them after connecting the tubing, be sure to use 2 monkey wrenches or spanners as shown. (Fig. 5-6)

If the flare nuts are over-tightened, the flare may be damaged, which could result refrigerant leakage and cause in injury or asphyxiation to room occu- pants.

●When removing or tightening the wide tube flare nut, use 2 monkey wrenches together: one at the wide tube flare nut and one at part A.(Fig. 5-7)

●For the flare nuts at tubing connections, be sure to use the flare nuts that were supplied with the unit, or else flare nuts for R410A (type 2). The refriger- ant tubing that is used must be of the correct wall thickness as shown in the table at right.

Apply refrigerant lubricant here and here

Fig. 5-4

Union Flare nut

Fig. 5-5

Torque wrench

Spanner

Indoor unit

Outdoor unit

Fig. 5-6

A

				Fig. 5-7
Tube diameter				Tightening torque,			Tube thickness
				approximate
φ		6.35 (1/4")		14 – 18 N · m	· cm)		0.8 mm
				(140 – 180 kgf
φ9.52 (3/8")				34 – 42 N · m	·	cm)	0.8 mm
				(340 – 420 kgf
φ			12.7 (1/2")	49 – 61 N · m	·	cm)	0.8 mm
				(490 – 610 kgf
φ	15.88 (5/8")			68 – 82 N · m	·		1.0 mm
				(680 – 820 kgf		cm)

Because the pressure is approximately 1.6 times higher than conventional refrigerant pressure, the use of ordinary flare nuts (type 1) or thin-walled tubes may result in tube rupture, injury, or asphyxi- ation caused by refrigerant leakage.

●In order to prevent damage to the flare caused by over-tightening of the flare nuts, use the table above as a guide when tightening.

●When tightening the flare nut on the narrow tube, use a monkey wrench with a nominal handle length of 200 mm.

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