Suburban Heating & Cooling

Air Conditioning Problems

There are not many air conditioner problems which homeowners can fix themselves, but there are a couple of things to check before you call for service.

If your air conditioner is not cooling like it should, use the following troubleshooting info to identify the problem.

Checking the Indoor Fan

If the indoor fan is not running, nothing else will work, so the fan is the first thing to check. To check the indoor fan, turn the thermostat Fan switch to ON. There may be a 30 second delay before the fan comes on.
If the fan does not come on, check the following, but keep in mind that the fan motor can sometimes run and still not move much (or any) air.
If part of the AC system is inside the house, it will have a light switch on it or near it. Sometimes those switches, particularly in attics and garages, get turned off by accident. If that switch is off, turn it on and try the Fan switch again.
Sometimes a tripped circuit breaker can be at fault. See "Circuit Breakers and Fuses" (below).
If you can hear the fan come on, check for air at the vents. If you are getting little to no air from the vents but can hear the fan running, the filter may be dirty, or the A/C may be low on Freon (either of which can cause the indoor coil to freeze over and block air flow). See "Indoor Fan Blows But A/C Unit Does Not Cool" in the section below.
If the the fan does not turn on, turn the A/C off and give us a call. Running the A/C when everything is not working correctly can cause more extensive damage.
If the fan runs then at least the fan is working. If the air is not cool or there is very little air, go to the "Indoor Fan Blows But A/C Unit Does Not Cool" section below.

Indoor Fan Blows But A/C Unit Does Not Cool

Check the air filter. Really dirty filters (or too many closed registers) can block air flow which reduces cooling and can cause the inside coil to ice over. Super-duper allergy filters can also block too much air flow and cause icing. Use cheaper, pleated filters--see "Picking the Correct Filter" (below). If the coil is iced over, you will get very little air (maybe none) from the vents--see "Outside Pipe Ices or Frosts" (below). If you suspect an iced coil, change the filter (or just remove it for now), open all registers and keep the unit off for a couple of hours or so to let any ice melt from the coil. While a really dirty filter or too many closed registers can cause a coil to ice, this condition is usually caused by a Freon leak—thawing out doesn't fix that. If thawing the system out and changing the filter doesn't solve the problem, you probably have a Freon leak. Turn the A/C off—a service call is needed.
If the indoor blower runs and provides plenty of air but the air is not cool, check the outdoor unit. With the thermostat set to Cool, the fan on the outdoor unit should be running. If not, check the outside circuit breakers (see below).
If the outside breakers/fuses are OK but the outside unit doesn't run (the outside fan is not running), turn the A/C OFF and give us a call. Running the A/C when everything is not working correctly can damage it further.
If the fan on the outside unit is running, check the temperature of the air blowing from the outside unit. On a properly working Air Conditioner, this air should be about as warm as a hair dryer. If it's not warm, the A/C unit is not working. A service call is required. If the air from the outside unit is really hot, the unit may be overloaded or need cleaning (see next).
If the air coming from the outside unit is hot (nearly hair dryer hot) but the inside air is still not cool, check the outside coil for debris (leaves, grass) or blockage (shrubs and fences). Turn the A/C off at the circuit breaker and clean the outside coils (the aluminum fin part) with a garden hose (not a power washer) to remove any debris that may be blocking the air flow and trim back the shrubs (provide at least a two-foot clearance around the unit). After cleaning the fins and trimming the shrubs, turn the A/C back on and check for cooling. If this doesn't solve the problem, turn the A/C unit off and give us a call.

Circuit Breakers and Fuses

Checking the circuit breakers. Most A/C units have two sets, one in the garage (or wherever your main electrical panel is located) and one attached to the house near the outside A/C unit (also called a "disconnect"). A circuit breaker is "tripped" when it's in the middle position--halfway between on and off. This should be readily noticeable. Find the tripped breaker and turn it off and then back on to reset it. The outside disconnect box may have fuses instead of breakers or may simply be a pull-out switch (in which case, your breakers are in another electrical panel—either inside the house or outside near the electric meter). If your outside disconnect uses fuses, you'll have to either check them (with a meter) or replace them with new fuses you know are good. Obviously, use the same type and size fuses. Amperage is very important. Do not supersize a fuse. Frequently tripping breakers or blowing fuses (more than once every few years) suggests an electrical problem that should be checked out. Tripping even once should be looked into. It could be caused by an overloaded unit and is often a sign maintenance is required.

Picking the Correct Filter

The blue fiberglass filters don't filter enough dirt. Instead, use a pleated filter and change them monthly (at least check them monthly). When selecting a pleated filter, get the cheaper, fuzzy kind. Super-duper allergy filters or pemanent washable filters restrict too much air flow even when new. Don't use filters with more than two pleats per inch. Also, the filter material should be fuzzy and not made from paper. Dirt Devil filters, for example, are made from a paper-like material and (in my opinion) restrict too much air flow, even though they don't have too many pleats. Filters with activated carbon or baking soda is a gimmick, but sometimes those are the cheapest and those filters are usually pretty good. In any case, get pleated (but not too many pleats) fuzzy filters and change them often. Also, do not put filters in the vents. They don't work and block too much air flow. If you need real allergy filtration, call us. There are several products that work, but they are not sold at home centers.

Outside Pipe Ices or Frosts

There are two copper pipes connecting the outside unit to the inside unit (some AC units are built with everything in one package and in that case, the copper pipes are inside, but may still be visible). If one of those pipes has ice or frost on it, it usually means the system is low on Freon (or the filter is really dirty). Running the AC when it's low on Freon increases your electric bill, can damage the compressor, and keeps the unit from cooling as well as it should.

Water in the Drain Pan and Other Water Problems

The A/C system removes moisture from your house and that water should drain freely from the white plastic pipe to outdoors. If there is water in the drain pan (in the case of indoor A/C systems) the plastic pipe could be clogged, or the unit could be low on Freon (which causes the indoor coil to ice up, blocking proper drainage). Either condition needs to be checked out. With outdoor units, water should only drain from the white plastic pipe and not from the sides of the case. Water draining from or collecting in the wrong place is a sure sign of a problem that needs prompt attention.