6 DIY AC Maintenance Tasks

Six jobs are safe for nearly any homeowner: checking airflow, changing the filter, using your senses, checking the thermostat, watching for ice, and spotting signs of a refrigerant leak. Anything that involves opening the cabinet, touching wiring or handling refrigerant belongs to a licensed technician.

Do these before the first hot stretch of the year and then keep an eye on them all summer. In Pasco, Kennewick and Richland, an air conditioner can go from idle to running most of the day within a week in June.

• Check airflow at every vent and return
• Change the filter
• Watch, listen and smell for changes
• Check the thermostat settings
• Look for ice on the coil or lines
• Watch for signs of a refrigerant leak

Airflow and the filter

Walk the house and make sure supply registers and return grilles are open and not blocked by furniture, rugs or curtains. Your system is sized on the assumption that air can move freely, and a blocked return in particular starves the blower.

Then look at the filter. A 1 inch filter usually wants replacing every one to three months, and sooner during dusty weeks, smoke season, or if you have pets. A dirty filter is the most common reason an air conditioner cools poorly, and it is the cheapest one to fix.

Use your senses

You know how your system normally sounds. Grinding, squealing, buzzing or a rattle that was not there last summer deserves a call. So does a burning smell or a musty odor when the system starts, and so does airflow that feels weaker than it used to. Also look at the outdoor unit. Keep a couple of feet of clear space around it, and remove leaves, cottonwood fluff and grass clippings from the outside of the cabinet after switching the system off at the thermostat.

Write down what you notice. A short note with the date, the sound and what the system was doing helps a technician far more than a report that it sounds funny. If you can, record a few seconds of the noise on your phone.

The thermostat

Confirm it is set to cool, that the setpoint is below the room temperature, and that the fan setting and schedule are what you intended. If the display is blank or dim, replace the batteries if it uses them. A surprising number of no-cooling calls turn out to be settings.

If you use a schedule or a vacation hold, check that an old setting is not overriding your setpoint. Also notice where the thermostat sits. One in direct sun or near a lamp or kitchen reads warm and can keep the system running longer than the house needs.

Ice on the coil or refrigerant lines

Frost on the indoor coil or on the larger copper line outside means something is wrong. The usual causes are restricted airflow, often a dirty filter, or low refrigerant. Switch the thermostat from cool to off and set the fan to on so it can thaw, then call. Running the compressor while iced up can damage it.

Signs of a refrigerant leak

Refrigerant is not used up like fuel, so a system that is low has a leak somewhere. Clues include warm air from the vents, a hissing sound, oily residue on the lines or fittings, and ice that keeps coming back. Topping up refrigerant without finding the leak only buys a short delay, and handling refrigerant takes a licensed technician.

A yearly tune-up closes the gap

Everything above is watching. A technician can measure refrigerant charge, test capacitors and electrical connections, and clean the coils, which you cannot do safely yourself. Air-Tech's AT Advantage Program maintenance plans include two visits a year. To set one up, or to have someone look at a problem from your list, call (509) 392-2021.