Armstrong A/C Troubleshooting Flowchart

Is your air conditioner... The problem might be your... What's wrong? How you can fix it
Thermostat The batteries in your thermostat may be dead, or the thermostat may not be on the correct setting. Put new batteries in your thermostat and ensure that it is on the cool setting.
Circuit breaker The breaker switch may have flipped. Move the breaker switch back to the “on” position.
Not blowing cold air? Air filter If the filter is clogged with debris or dust, it won’t be able to do its job. Replace or clean your air filter so that air can flow freely.
Outside unit The air conditioner may not be able to have air flowing freely if there are dirt and debris around the unit. Make a two-foot space around your unit that is clear and free of leaves, greenery and any other blockage so that it can vent air properly.
Refrigerant If the refrigerant is leaking, your unit will not be efficient at cooling since there is less cooling fluid to run through your unit. Get a technician who can solve this problem.
Insulation Insulation is important to keep air from leaking out. Cracks, old windows and doors are all spots where cold air can escape. Windows are the main places where cool air escapes. Consider upgrading to insulated windows or use blackout curtains.
Dripping water? Condensate line The pipe that exits your air conditioner could be clogged. Blow compressed air through the pipe to dislodge the clog.
Drain line Water can overflow in the drain pan if the drain pipe is blocked. Check the drain line for any clogs and remove them.
Making odd sounds? Blower motor or belt Squealing sounds can come from the belt or the blower motor. Use lubricant on the parts to help them run better without squeaking.
Fan blades If the sound is repetitive like a card stuck in a bicycle spoke, there is a chance something is caught between the blades. Switch your unit off and check the fan blades to see if anything is trapped and remove it carefully.