Preventive Maintenance 

Look for signs of corrosion on fins, cabinet, copper tubing and solder joints. Look for excessive or unusual vibration for fan blades or sheet metal panels when in operation. Identify fan cell(s) causing vibration and check the motor and blade carefully. Look for oil stains on headers, return bends, and coil fins. Check any suspect areas with an electronic leak detector. Check drain pan to insure that drain is clear of debris, obstructions, or ice buildup, and is free-draining.

Periodic cleaning can be accomplished by using a brush, pressurized water or a commercially available evaporator-coil cleaner, or mild detergent. Never use an acid-based cleaner. Follow label directions for appropriate use. Be sure the product you use is approved for use in your particular application. Flush and rinse coil until no residue remains. Pay close attention to the drain pan, drain line, and trap.

Check that each fan rotates freely and quietly. Replace any fan motor that does not rotate smoothly or makes an unusual noise. Check all fan set screws, and tighten if needed. Check all fan blades for signs of stress or wear. Replace any blades that are worn, cracked, or bent. Verify that all fan motors are securely fastened to the motor rail. Lubricate motors if applicable.

Visually inspect all wiring for wear, kinks, bare areas, and discoloration. Replace any wiring found to be damaged. Verify that all electrical and ground connections are secure; tighten if necessary. Check operation/calibration of all fan cycle and defrost controls when used. Look for abnormal accumulation of ice patterns and adjust defrost cycles accordingly. Compare actual defrost heater-amp draw against unit data plate. Visually inspect heaters to ensure even surface contact with the coil. If heaters have crept, decrease defrost termination temperature and be sure you have even coil-frost patterns. Re-align heaters as needed. Check drain-line heat tape for proper operation (supplied and installed by others).

Check unit cooler superheat and compare reading for your specific application. Visually inspect coil for even distribution.

Look for signs of oil stains on interconnection piping and condenser coil. Pay close attention to areas around solder joints, building penetrations, and pipe clamps. Check any suspect areas with an electronic leak detector. Repair any leaks found and add refrigerant as needed. Check condition of moisture indicator/sightglass in the sight glass if so equipped. Replace liquid-line drier if there is indication of slight presence of moisture. Replace refrigerant, oil, and drier if moisture concentration is indicated to be high. Check moisture indicator/sightglass for flash gas. If found, check entire system for refrigerant leaks, and add refrigerant as needed after repairing any leaks. Check compressor sightglass (if equipped) for proper oil level. Check condition of condenser. Look for accumulation of dirt and debris (clean as required). Check for unusual noise or vibration. Take corrective action as required. Inspect wiring for signs of wear or discoloration and repair if needed. o Check and tighten all flare connections.

Repeat all quarterly inspection items for Air-Cooled Condensing Units.

Periodic cleaning can be accomplished by using a brush, pressurized water and a commercially available foam-coil cleaner. If foam cleaner is used, it should not be an acid-based cleaner. Follow label directions for appropriate use.

Rinse until no residue remains.

Check that each fan rotates freely and quietly. Replace any fan motor that does not rotate smoothly or makes excessive noise.

Check all fan-blade set screws and tighten as required.

Check all fan blades for signs of cracks, wear, or stress. Pay close attention to the hub and spider. Replace blades as required.

Verify that all motors are mounted securely.

Lubricate motors if applicable. Do not lubricate permanently sealed, ball-bearing motors.

Periodic cleaning can be accomplished by using a brush, pressurized water, and a commercially available foam-coil cleaner. If foam cleaner is used, it should not be an acid-based cleaner.

Follow label directions for appropriate use.

Rinse until no residue remains.

Verify that all electrical and ground connections are secure; tighten as required.

Check condition of compressor and heater contactors. Look for discoloration and pitting. Replace as required.

Check operation and calibration of all timers, relays, pressure controls, and safety controls.

Clean electrical cabinet. Look for signs of moisture, dirt, debris, insects, and wildlife. Take corrective action as required.

Verify operation of crankcase heater by measuring amp draw.

Check suction, discharge and net oil pressure readings. If abnormal, take appropriate action.

Check operation of demand cooling, liquid injection, or unloaders, if so equipped.

Check pressure drop across all filters and driers. Replace as required. o Verify that superheat at the compressor conforms to specification. (30°F to 45°F)

Check pressure and safety control settings and verify proper Operation.

Look for high concentrations of acid or moisture. Change oil and driers until test results read normal.

Investigate source of high metal concentrations, which normally are due to abnormal bearing wear.

Look for liquid refrigerant in the crankcase, low oil pressure, or low superheat as a possible source.

If the accumulator is insulated remove insulation and inspect for leaks and corrosion.

Pay close attention to all copper-to-steel brazed connections.

Wire brush all corroded areas and peeling paint.

Apply an anticorrosion primer and paint as required. Re-insulate if Applicable.