27readily. POE oils can absorb 15 times as much water as other oilsdesigned for HCFC and CFC refrigerants. Take all necessaryprecautions to avoid exposure of the oil to the atmosphere.Servicing Systems on Roofs with Synthetic MaterialsPOE (polyolester) compressor lubricants are known to cause longterm damage to some synthetic roofing materials. Exposure, even ifimmediately cleaned up, may cause embrittlement (leading tocracking) to occur in one year or more. When performing anyservice that may risk exposure of compressor oil to the roof, takeappropriate precautions to protect roofing. Procedures which riskoil leakage include, but are not limited to, compressor replacement,repairing refrigerant leaks, replacing refrigerant components suchas filter drier, pressure switch, metering device, coil, accumulator,or reversing valve.Synthetic Roof Precautionary Procedure1. Cover extended roof working area with an impermeablepolyethylene (plastic) drip cloth or tarp. Cover anapproximate 10 x 10 ft (3 x 3 m) area.2. Cover area in front of the unit service panel with a terrycloth shop towel to absorb lubricant spills, prevent run--offs,and protect drop cloth from tears caused by tools orcomponents.3. Place terry cloth shop towel inside unit immediately undercomponent(s) to be serviced and prevent lubricant run--offsthrough the louvered openings in the unit base.4. Perform required service.5. Remove and dispose of any oil contaminated material perlocal codes.Liquid Line Filter DrierThe filter drier is specifically designed to operate with Puron. Useonly factory--authorized components. Filter drier must be replacedwhenever the refrigerant system is opened. When removing a filterdrier, use a tubing cutter to cut the drier from the system. Do notunsweat a filter drier from the system. Heat from unsweating willrelease moisture and contaminants from drier into system.Puron (R--410A) Refrigerant ChargingRefer to unit information plate and charging chart. Some R--410Arefrigerant cylinders contain a dip tube to allow liquid refrigerant toflow from cylinder in upright position. For cylinders equippedwith a dip tube, charge Puron units with cylinder in uprightposition and a commercial metering device in manifold hose.Charge refrigerant into suction--line.TROUBLESHOOTINGRefer to the Troubleshooting Chart (Table 10) for troubleshootinginformation.START--UP CHECKLISTUse the Start--Up Checklist at the back of this manual.50VL-- A