AIR PURGEEvacuate the air in the connecting pipes and in theAlign the centers of the connecting pipes and tighten indoor unit using a vthe flare n acuum pumput as f .ar as possib Do not use thele with y refrour fingers igerCAUTIONDo not apply excess torque.Otherwise, the nut may crack depending on theconditions.••ant in the outdoor unit.. For detailsThen , see thetighten the n manut with a spanner and torque wrench as ual of the vsho acuum pumpwn in the figure ..Fig. 10-4-5acuum pump>Be sure to use a vacuum pump with counter-flowprevention function so that inside oil of the pump doesnot flow backward into pipes of the air conditionerwhen the pump stops. (If oil inside of the vacuum pumpenters into the air conditioner, which use R410A,refrigeration cycle trouble may result.)Flare nutHalf unionUse a wrench to secure. Use a torque wrench to tighten.1. Connect the charge hose from the manifExternallythreaded sideold valvInternallythreaded sidee tothe service port of the gas side packed valve.2. Connect the charge hose to the port of the vacuumpump.3. Open fully the low pressure side handle of thegauge manifold valve.4. Operate the vacuum pump to start evacuating.Perform evacuating for about 15 minutes if thepiping length is 20 meters. (15 minutes for20 meters) (assuming a pump capacity of 27 litersper minute. Then confirm that the compoundpressure gauge reading is -101 kPa (76 cmHg).5. Close the low pressure side valve handle of gaugemanifold.6. Open fully the valve stem of the packed valves(both side of Gas and Liquid).7. Remove the charging hose from the service port.8. Securely tighten the caps on the packed valves.Fig. 10-4-7Tightening torque of flare pipe connectionsThe operating pressure of R410A is higher than that ofR22. (Approx. 1.6 times).It is therefore necessary to firmly tighten the flare pipeconnecting sections (which connect the indoor andoutdoor units) up to the specified tightening torque.Incorrect connections may cause not only a gasleakage, but also damage to the refrigerant cycle.Fig. 10-4-6(Unit : N•m)Outer dia. Tightening torqueof copper pipe∅6.35 mm 16 to 18 (1.6 to 1.8 kgf·m)ˇ 9.52 mm 30 to 42 (3.0 to 4.2 kgf·m)Flare atindoor unit sideFlare atoutdoor unit side∅FILE NO. SVM-16003- 56 -Pressure gaugeManifold valve–101 kPa (-76 cmHg)Handle LoConnecting pipeCompound pressure gaugeVacuumpumpHandle Hi (Keep full closed)Charge hose (For R410A only)Vacuum pump adapter forcounter-flow prevention(For R410A only)Packed valve at gas sideService port (Valve core (Setting pin))Packed valve at liquid sideCharge hose (For R410A only)
