Panasonic 26PEK2U6 26PEK2U6 Service Manual - Page 121

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 matching surfaces of the flare and union before connecting them together. This is effective for reducing gas leaks. (Fig. 1-17) (3) For proper connection, align the union tube and flare tube straight with each other, then screw on the flare nut lightly at first to obtain a smooth match. (Fig. 1-18) 1. Specifications Apply refrigerant lubricant Fig. 1-17 Adjust the shape of the liquid tube using a tube bender at the installation site and connect it to the liquid tubing side valve using a flare. Cautions During Brazing Union Flare nut Fig. 1-18 Replace air inside the tube with nitrogen gas to prevent copper Torque wrench 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 Indoor unit Spanner valves to become damaged. Therefore allow the tubing to cool when brazing. Use a reducing valve for the nitrogen cylinder. 1 Outdoor unit Fig. 1-19 Do not use agents intended to prevent the formation of oxide film. These agents adversely affect the refrigerant and refrigerant oil, and may cause damage or malfunctions. 2. Connecting Tubing between Indoor and Outdoor Units (1) Tightly connect the indoor-side refrigerant tubing extended from the wall with the outdoor-side tubing. (2) To fasten the flare nuts, apply specified torque as shown at right. A When removing the flare nuts from the tubing connections, or when tightening them after connecting the tubing, be sure to use 2 adjustable wrenches or spanners. (Fig. 1-19) If the flare nuts are over-tightened, the flare may be damaged, which could result in refrigerant leakage and cause injury or asphyxiation to room occupants. When removing or tightening the gas tube flare nut, use 2 adjustable wrenches together: one at the gas tube flare nut, and one at part A. (Fig. 1-20) 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 refrigerant tubing that is used must be of the correct wall thickness as shown in the table at right. Fig. 1-20 Tube diameter ø1/4" (6.35 mm) ø3/8" (9.52 mm) ø1/2" (12.7 mm) ø5/8" (15.88 mm) Tightening torque (approximate) 120 - 160 lbf · in. \140 - 180 kgf · cm^ 300 - 360 lbf · in. \340 - 420 kgf · cm^ 430 - 480 lbf · in. \490 - 550 kgf · cm^ 590 - 710 lbf · in. \680 - 820 kgf · cm^ Tube thickness (in.) t0.032 t0.032 t0.032 t0.04 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 asphyxiation 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 liquid tube, use an adjustable wrench with a nominal handle length of 7-7/8 in. 1-113