Checklist: Air Conditioner Maintenance
 
Checklist: Air Conditioner MaintenanceHomeowners can following this checklist to maintain their air conditioning units:

Check the outside condensing unit
The first thing to check before turning on your unit is to make sure the condensing unit located outside is not covered up. The unit needs to draw air into the system in order to have something to cool and circulate inside, but the process is hindered if it cannot pull in enough outside air. (We're amazed how many homeowners call because their air conditioner isn't cooling, only to find they forgot they had temporarily stacked lawn furniture, bags of leaves and lawn clippings, around their unit over the winter.)

Some people intentionally cover their condenser to protect it from the elements during the winter, although these units require no protection since they are designed for outdoor installation.

Run your air conditioner before regular use
Run your air conditioner for a few minutes in late spring or early summer, before you need it. If you wait until the first hot day to discover it isn't working, you'll find yourself on a waiting list, sweltering for days before an air conditioning specialist can come to fix it.

Change the air conditioner's filters regularly.
Dirty filters restrict air flow, reduce efficiency and worse case, can cause the evaporator to ice up. Disposable fiberglass filters should be replaced. Electrostatic or electronic filters need to be washed regularly.

Check the access panels
Be sure all access panels are secure, with all the screws in place.

Check for obstructions
Clean obvious obstructions such as newspaper and leaves from around the exterior of the unit.

Set the correct mode
Be sure the thermostat is set in the cooling mode. Just setting the dial below room temperature will not activate the air conditioning if it is set in the heat mode.

Never use water to clean your air conditioning system
A thoroughly cleaned air conditioning unit will operate at top efficiency. However, homeowners are strongly discouraged from using a hose and water to try to clean it themselves because of the very serious risk of electrical shock and possible shorting of electrical components.

Thomas Fishler, Thomas Fishler's Heat & Air Conditioning & Duct Cleaning, Carmichael, California.