Seasonal Commercial HVAC Maintenance
Inspected this coil to ensure proper cooling capacity levels. Clean it on an as-needed basis using a commercial coil cleaner or dishwasher detergent in a pressurized spray canister. Wash both sides of the coil and flush with clean water. For best results, backflush toward the return-air section to remove foreign material. Be careful not to overflow the evaporator drain condensate pan.
Inspected the condenser coil monthly and clean it annually as required by location and outdoor air conditions. This cleaning ensures proper condensing temperature, eliminates both low capacity level and poor efficiency. Wash one-row coils with a commercial cleaner. For coils with multiple rows, use a water hose or other suitable equipment to flush down between multiple sections to remove dirt and debris.
Filters should be cleaned or replaced at the start of each cooling and heating season, or more often if operating conditions require. To determine the frequency, visually inspect or measure the airside pressure drop. Clean filters prevent dirt buildup on coils and help with the indoor air quality of the occupied building space. Follow the manufacturer recommendation for filter size and type.
Outdoor air inlet screens.
Annually clean inlet screens with steam or hot water and mild detergent. Inspect monthly to determine if more frequent cleaning is required.
Charge the compressor(s) with the correct amount of oil at the factory. With semi-hermetic compressors, refer to the manufacturer instructions for checking proper oil level.
Fan motor bearings. Depending on the type of unit, the fan motor bearings may be of the permanently lubricated type. If the bearings are not permanently lubricated, lubricate every six months with suitable bearing grease or oil. See the manufacturer recommendation on oil manufacturer and type to use.
Check the condenser fan height annually to prevent re-circulation of condenser air and maintain the capacity and efficiency of the unit.
Inspect the evaporator fan to ensure it’s centered in its housing. Annually lube the evaporator fan motor, if needed.
Inspect the blower belt for wear, proper tension, and pulley alignment at the beginning of each cooling and heating season, or as conditions require. Replace worn belts. Don’t run them to the point of breakage. Annual inspections will indicate how often to replace belts.
Thermostatic expansion valve (TXV).
If the unit contains thermostatic expansion valves, check each circuit to ensure the bulb is secure and insulated and in the correct position per the manufacturer recommendation. Most TXVs are factory set, non-adjustable, and require no service.
If the unit contains an economizer, perform an annual cycle run-through to ensure the actuator, dampers and temperature sensors are operating correctly. Also check the ventilation settings.
Check the refrigerant charge annually to make sure it is at the proper level. Before checking charge, run the unit for 15 minutes in the cooling mode to stabilize system pressure. The correct amount of refrigerant charge is listed on the unit nameplate. Use the manufacturer’s cooling charging chart to determine if additional refrigerant is required.
When evaluating the charge, adjustment to the specified factory charge must always be minimal. If a substantial adjustment is indicated, an abnormal condition exists somewhere in the cooling system, such as a refrigerant leak or insufficient airflow across either the coil or both coils.