Air filters maintenance
After specifying a filter media and selecting a filter, it's important to pay close attention to proper filter installation. The goal is to avoid bypass air by making sure that all the air in the system goes through the filter. Bypass air causes contamination in housings, coils, fans, and ducts.
For all of these reasons, it is crucial to establish the appropriate filter change strategy.
Filters should be changed immediately if they become wet, microbial growth on the filter media is visible, or when filters collapse or become damaged to the extent that air bypasses the media.
Make the job of filter changing as easy as possible. One tip is to place labels on the housing units with information such as the number and type of filters, date changed, and pressure-drop. Air handlers that are located in difficult-to-access places will be more likely to suffer from poor air filter maintenance and overall poor maintenance. Therefore, quick release and hinged access doors for maintenance are more desirable than bolted access panels when security is not an issue.
When changing the filter, make sure that the replacement filter is of the correct size and compatible with your housing. Review the performance value of the filter to ensure the pressure drop across the filter will not be too great, especially as the filter loads. The greater resistance will reduce the air flow to the unit, creating a negative impact on the unit's heating/cooling efficiency and energy efficiency.
Time filter change-outs so they occur when the facility is unoccupied. This will help to avoid problems associated with disruptions in the HVAC system, and possible distribution of odours or emissions. If filters must be changed when the facility is occupied, turn off the supply fans to prevent debris from entering the ductwork downstream of the filters. Similarly, the entire filter area should be cleaned and wiped down while fans are off. Use a clean rag instead of compressed air to wipe dust from the inside of the filter housing and around gasket surfaces. When removing a spent filter, take care to avoid dropping contaminants into the ductwork.
At the end of the day, it is important to follow the recommendations of the filter manufacturer/supplier and HVAC system supplier to determine the proper procedures and frequencies for maintaining and changing filters. And don't forget to fully document all inspections and corrective actions.