As the qualified technician performs your scheduled maintenance, he/she will be carefully observing, testing, cleaning, and analyzing your system.
Check for signs of corrosion on fins, cabinet, copper tubing, and solder joints, excessive or unusual vibration of fan blades or sheet metal panels. Look for oil stains on headers, return bends, and coil fins. Check any suspect areas for leaks with an electronic leak detector. Check drain pan to ensure that drain is clear of debris, obstructions or ice buildup and is free draining.
Clean evaporator coil and blades
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 of cleaning agents. Be sure the product you use is approved for use for your particular application. Flush and rinse coil until no residue remains. Pay close attention to drain pan, drain line and trap.
Check the operation of all fans and ensure airflow is unobstructed:
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.
Inspect electrical wiring and components
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.
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. Verify that superheat at the compressor conforms to specification. (30°F to 45°F). Check pressure and safety control settings and verify proper operation.
In addition to quarterly and semiannual maintenance checks, your contractor will submit an oil sample for analysis. Look for evidence of acid or moisture. Change oil and driers until test results read normal. High metal concentrations should be analyzed and diagnosed.
Inspect suction accumulator (if equipped)
If the accumulator is insulated, your technician will likely 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.
By scheduling your equipment’s recommended maintenance in advance and hiring a Heatcraft Certified Contractor, your investment can operate more efficiently, conserve more energy, and even help save on energy costs. When is your unit due for service?