Aaon HVAC Unit RN-018-3-0-EJ

Measure the temperature of the liquid line as it leaves the condenser coil

Read the gauge pressure at the liquid line close to the point where the temperature was taken

Convert the pressure obtained to a saturated temperature using the appropriate refrigerant temperature-pressure chart

Subtract the measured liquid line temperature from the saturated temperature to determine the liquid sub-cooling

Compare calculated sub-cooling to the table below for the appropriate unit type and options

Check for debris or foreign matter in the vent outlet

Is the vent outlet clear of debris?

Remove any debris found in the vent outlet

Was the vent outlet cleaned successfully?

Check vent outlet each time air filters are changed

Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts

Filter Inspection and Replacement

Open access door and pull filters straight out to inspect all of the filters

Replace filters with the size indicated on each filter or as shown in the tables

Ensure arrow on the replacement filters points towards the blower

Verify that all filters are properly installed

Ensure the following items are ready

Pump the cleaning liquid through the exchanger

Ensure the cleaning solution flow rate is at least 1.5 times the normal flow rate

Was the cleaning performed in a back-flush mode?

Rinse the heat exchanger with clean water

Use a solution of 1-2% sodium hydroxide or sodium bicarbonate before the last rinse to neutralize any remaining acid

Gather necessary cleaning tools and materials

Inspect the drain pan for any visible debris or blockage

Remove any debris from the drain pan

Clean the drain pan with an appropriate cleaning solution

Is the drain line clear and unobstructed?