Panasonic CU-3KS19NBU Technical & Service Manual

Also see for CU-3KS19NBU: Operating instructions Installation manual

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Panasonic CU-3KS19NBU Technical & Service Manual Manual pdf 107 page image

21 Pump Down When relocating or disposing of the air conditioner, request thisservice from the dealer where the unit was purchased, or from anappropriate agent. Perform pump-down as described below.What is pump-down? Pump-down refers to recovering the refrigerant gas from the refrig-erant cycle at the outdoor unit. This work must be performed dur-ing cooling operation. The refrigerant gas cannot be recoveredduring heating operation. During winter, or if the temperature sensor prevents cooling opera-tion, perform “forced cooling operation.”Pump-down procedure(1) Fully close the spindles at the valves on the narrow tube side oftubes A, B, C and D. (Refer to Fig. 22.)(2) Connect the manifold gauge to the charging port at the valve onthe wide tube side of tube D. Purge the air from the charging hose.(Refer to Fig. 23.)(3) Perform cooling operation or forced cooling operation.When the pressure at the low-pressure side is 0.05 – 0.1 MPaG(0.5 – 1 kg/cm2G), fully close the spindles at the valves on thewide tube side of tubes A, B, C, and D, and immediately stopoperation. (Refer to Fig. 23.)In the winter, the outdoor unit may stop after 5 - 10 minutes ofoperation. This is in order to protect the indoor unit heatexchanger from freezing and does not indicate a problem.(4) Disconnect the manifold gauge and the inter-unit tubes, andattach the caps and flare nuts. At this point, pump-down is com-pleted. (If the caps and flare nuts are not reattached, there is thedanger of gas leakage.) (Refer to Fig. 24.)If pump-down is not possibleIf the air conditioner cannot be operated because of a malfunction orother cause, use a refrigerant recovery device to recover the refrigerant.In order to protect the earth’s environment, be sure to perform pump-down to recover refrigerantgas without releasing it into the atmosphere.Fig. 22(11) Replace the flare nut on the wide tube service port and fasten the flare nut securely with an adjustable wrench orbox wrench. Next, mount the valve cap and tighten it with a torque wrench (the cap needs to be tightened with thetorque of 180 lbs·in (200 kgf·cm)). This process is very important to prevent gas from leaking from the system.(12) Test run the air conditioner. (See page 26.)(13) While the air conditioner is running, apply liquid soap to check for any gas leaks around the service valves or caps.(14) If there is no leakage, stop the air conditioner.(15) Wipe off the soap on the tubing.This completes air purging with a vacuum pump and the air conditioner is ready for actual operation.Fig. 23CDBAManifold gaugeWide tube sideCharging hoseCapCapCapCapAfter disconnectingthe inter-unit tubes,attach the flare nutswith flare bonnets.Fig. 24DCBACharging portNarrow tube sideCloseCloseCloseClose