Carrier 42NQV025H Service Manual

Contents

– 63 –Tightening ConnectionAlign the centers of the connecting pipes and tightenthe flare nut as much as possible with your fingers.Then tighten the nut with a wrench and torquewrench as shown in the figure.Fig. 10-4-7CAUTION• Do not apply excessive force.Otherwise, the nut may break.(Unit : N·m)• Tightening torque for connection of flare pipeThe pressure of R410A is higher than R22.(Approx. 1.6 times.) Therefore securely tighten theflare pipes which connect the outdoor unit and theindoor unit with the specified tightening torqueusing a torque wrench.If any flare pipe isincorrectly connected,it may cause not onlya gas leakage but alsotrouble in therefrigeration cycle.Outer dia. of copper pipeØ6.35 mmØ9.52 mmØ12.7 mmTightening torque14 to 18 (1.4 to 1.8 kgf•m)33 to 42 (3.3 to 4.2 kgf•m)50 to 62 (5.0 to 6.2 kgf•m)Fig. 10-4-8Half union Flare nutExternallythreaded side Internallythreaded sideUse a wrenchto secure. Use a torque wrenchto secure.Flare atindoor unitsideFlare atoutdoor unitside10-4-4. EvacuatingAfter the piping has been connected to the indoorunit, perform the air purge.AIR PURGEEvacuate the air in the connecting pipes and inthe indoor unit using a vacuum pump.Do not use the refrigerant in the outdoor unit.For details, see the vacuum pump manual.Fig. 10-4-9CAUTION• IMPORTANT POINTS FOR PIPING WORK1. Keep dust and moisture from entering thepipes.2. Tighten connections carefully (between pipesand unit).3. Evacuate the air in the connecting pipesusing a VACUUM PUMP.4. Check for gas leaks at all connections.Use a vacuum pumpBe sure to use a vacuum pump with counter-flowprevention function so that oil inside the pump doesnot flow back into the air conditioner pipes when thepump stops. (If oil inside the vacuum pump entersinto the air conditioner circuit which uses R410A,trouble with the refrigeration system may develop.)1. Connect the charge hose from the manifold valveto the service port of the gas side packed valve.2. Connect the charge hose to the port of thevacuum pump.3. Open fully the low pressure side handle of thegauge manifold valve.4. Operate the vacuum pump to begin evacuating.Perform evacuating for about 15 minutes if thepiping length is 20 meters (15 minutes for 20meters) (assuming a pump capacity of 27 litersper minute).Confirm that the compound pressure gaugereading is –101 kPa (76 cmHg).5. Close the low pressure valve handle of gaugemanifold.6. Open fully the valve stem of the packed valves(both sides of Gas and Liquid).7. Remove the charging hose from the service port.8. Securely tighten the caps on the packed valves.FILE NO. SVM-07013-1Packed valve at liquid sideService port (Valve core (Setting pin))Packed valve at gas sideVacuumpumpVacuum pump adapter forcounter-flow prevention(For R410A only)Charge hose(For R410A only)Handle Hi(Keep full closed)Compound pressure gauge-101kPa (76cmHg)Pressure gaugeManifold valveHandle LoCharge hose (For R410A only)Connecting pipe