Watching Those Filters

How To Clean The Indoor Unit Air Filters On Your Mini-Split Heat Pump

Mini-split heat pumps are low maintenance, unobtrusive devices, but they do require occasional attention. An important maintenance task you will need to address from time-to-time is cleaning the air intake filter located inside the evaporator unit. This task is simple for you to perform and will keep your mini-split heat pump operating at its most efficient level. Here are the tools and materials you need, as well as a step-by-step procedure for cleaning air filters:

Tools and materials needed

  • Sink with running water

  • Soft-bristled plastic brush

  • Grease-cutting liquid dish soap

  • Hair dryer

Step-by-step procedure

1. Power down the indoor air-handling unit - Before performing maintenance, be sure to turn off the unit using the remote control, if it is equipped, or by flipping the on-board switch. You do not need to completely disconnect the power to clean the filter.

2. Remove the cover to the indoor unit - Once the unit has turned off, wait for the automated vent cover to return to its parked position. After the cover has parked itself, remove it from the unit by pressing the release buttons that hold it in-place; these will be marked on your unit. For some units, the cover will only lift up and will not be removed, so don't force a cover if it appears fixed in its position. Liftable covers use an extendable leg that holds the cover up while you perform maintenance.

3. Locate and remove the air filters - Your mini-split unit may use one or more air intake filters; regardless, all can be removed for cleaning. The filters curve around the front of the unit's evaporator coils and will consist of thin foam pieces that are held within a flexible frame. Each filter will be held in place by clips on the top and bottom; simply squeeze the bottom edge of the filter inward and lift it out of position.

In addition, look for other smaller, specialized filters such as ionization filters; these usually can't be cleaned but can be replaced on an as-needed basis. Be sure to follow your manufacturer's recommendations for replacement or change them out if obviously dirty. For some units, these specialized filters aren't necessary for operation and can be removed altogether.

4. Clean the air intake filters - After removing the intake filters, place them inside a sink filled with warm water and a teaspoon of grease-cutting liquid dish soap. Swirl the water around with your hands and lift the filters in and out of the sink to force water through the foam.

If the filters still appear to be dirty after a couple of minutes of cleaning, you can use a soft plastic bristled brush to lightly scrub the stubborn debris. Be gentle, or you may tear the foam and be forced to purchase new filters.

Once the filters are clean, hold them under running water and rinse away all the soap suds. Allow the filters to air dry before placing them back into the unit. You can also use a hair dryer to accelerate the drying process if you are in a hurry.

5. Replace the filters - After cleaning the filters and allowing them to dry completely, install them in the unit by pushing the top edges into their slot behind the top clips and curl the bottom edges of the filters inward and slip them behind the bottom clips. Be sure the filters are lined-up correctly and fully in-place before proceeding.

6. Replace the cover - Once the filters are back in position, you can replace the cover. However, before pushing the cover back into place, be sure you follow the procedures for replacement. Once again, reference the face of the unit to locate information about how to replace the cover properly; improper placement can cause the unit to malfunction or flash an error code on its display. Restore power to the unit and allow it to run a self-check and resume operation.

For more information and tips, contact a local HVAC company like Cape Fear Air Conditioning & Heating Co., Inc.