Sanyo CLM2472 Service Manual - Page 84

4. Air Purging Air and moisture remaining in the refrigerant system have undesirable effects as indicated below. Therefore, they must be purged completely. G pressure in the system rises G operating current rises G cooling efficiency drops G moisture in the air may freeze and block capillary tubing G water may lead to corrosion of parts in the refrigerant system Service valve on narrow Service valve on wide tube side I Air Purging with a Vacuum Pump (for Test Run) With push-pin G In order to protect the earth's environment, be sure to use a vacuum pump to perform the air purge. (Never perform an air purge by using the refrigerant gas cylinder or other external gas, or by using the gas inside the outdoor unit.) D Manifold gauge C (special for R410A) B Low-pressure High-pressure valve valve Vacuum pump A Leave the Lo Hi adapter (for preventing valve open. Open reverse flow) (special for R410A) Hex wrench Charging hose (special for R410A) Fig. 20 Vacuum pump CAUTION In order to prevent charging errors with A/C that uses R410A, the screw diameter at the service valve charging port has been changed. When recharging or performing other servicing, use the special charging hose and manifold gauge. Perform the air purge for tubes A, B, C, and D. Use the same procedures for all tubes. (1) Check that each tube (both narrow and wide tubes) between the indoor and outdoor units have been properly connected and all wiring for the test run has been completed. Note that both narrow and wide tube service valves on the outdoor unit are kept closed at this stage. Stopper Spindle Service port Screw diameter: 1/2 UNF 20 threads Valve core Cap tightening torque: 170 - 215 lbs·in (200 - 250 kgf·cm) (Tighten by hand, then use a wrench to turn.) (2) Using an adjustable wrench or box wrench, remove the valve caps from the service valve on both narrow and wide tubes. (3) Connect a vacuum pump and a manifold valve (with Cap nut tightening torque: 60 - 95 lbs·in (70 - 110 kgf·cm) (Tighten by hand, then use a wrench to turn approximately 30 .) pressure gauges) to the service port on the wide tube service valve. (Fig. 20). NOTE CAUTION Before using the vacuum pump adapter, read the vacuum pump adapter manual, and use the External diameter of service port R410A: 5/16" Fig. 21 adapter correctly. CAUTION Be sure to use a manifold valve for air purging. If it is not available, use a stop valve for this purpose. The "Hi" knob of the manifold valve must always be kept closed. G When using a hex wrench to open the spindle, an extremely small amount of refrigerant may leak. This does not indicate a problem. G Use a hex wrench of a type to which force can be easily applied. 18