17Installation ProcedureVacuum pumpingWith a vacuum pump, create vacuum from the stop valve of the outdoor unit.Emptying with refrigerant sealed in the outdoor unit is absolutely forbidden.Open all valvesOpen all the valves on the outdoor unit.Gas leakage detectionCheck with a leakage detector or soap water that if there is gas leakage at the pipeconnections and bonnets.Insulation treatmentConduct insulation treatment on both the gas side and liquid side of pipes respectively.During cooling operation, both the liquid and gas sides are cold and thus shall be insulatedso as to avoid dew generation.The notch upward (Attached detail view)Indoor unit Subsidiary insulation tubeField piping side2When the unit have the Return air box (see the following picture) when shippingfrom the factory and they are of back-side return air type.R22:Series 07R22:Series 24R22:Series 09-21R407C:Series 07-24CautionsNOTEThe insulating material at gas side shall be resistant to a temperature above 120*.The indoor unit pipe connection part shall be insulated.The connection of indoor unit pipes must use double spanners.The installing torque shall be as given in the following table.Double-spanneroperationConnecting pipeO.D.(mm)ÿ6.35ÿ9.52ÿ12.70ÿ15.88Installing torque(N-m)11.8 (1.2kgf-m)24.5 (2.5kgf-m)49.0 (5.0 kgf-m)78.4 (8.0 kgf-m)Increased installingtorque (N-m)13.7 (1.4 kgf-m)29.4 (3.0 kgf-m)53.9 (5.5 kgf-m)98.0 (10.0 kgf-m)Pipe expansion dimensions as follows:Slope Damage Bur Partial OverlongCorrect Incorrect6.35 mm (1/4") 0.8 ~ 1.59.52 mm (3/8") 1.0 ~ 1.812.7 mm (1/2") 1.2 ~ 2.015.88 mm (5/8") 1.4 ~2.2Pipe diameter ÿ Size A (mm)