Before you call a air conditioning service repair man to check your air conditioner that’s not cooling you may want to check some of these possible causes. First and most obvious is to be sure your system air filter is not restricted. In many cases this will cause your evaporator or indoor coil to freeze up. If the system has a fan v-belt make sure it is not cracked broke or slipping. If the evaporator coil is froze up you may notice condensate leaking in and around the furnace, air handler or window type A/C unit. Another more apparent sign would be actually seeing ice build up on the coil or refrigeration lines connecting the evaporator and condenser.

Another cause for your system freezing up could be closed or blocked supply registers. In some cases people will close registers to unoccupied areas of their home for energy savings but closing to many can cause more problems than it’s worth. System freeze ups can also be related to a lose of refrigerant with in your air conditioner. If your system is low on refrigerant you will have to have a qualified air conditioning repair technician locate and repair the leak as well as properly recharge the system. Any time your air conditioner system is froze up you should place the thermostats fan switch to the on position and the cool system switch to off for a long enough time to allow the coils to completely thaw. After checking some or all of the potential problems you can try to run the air conditioner again. If you have air blowing out of your supply registers but it’s not cool you will want to check the condenser or out door unit to be sure it is running. If you do not hear anything running check the breaker or disconnect switch at the condenser. Their may also be bad fuses in the disconnect box. Tripped breakers or blow fused are typically caused by problems that need to be addressed by a technician . It is possible that a power surg or electrical storm could also cause a breaker to trip and once you reset it the system will be fine. Another common cause for the condenser not functioning is a broken or shorted low voltage wire. Mice and other rodents will tend to chew though these wires. The low voltage wire is typically a small two conductor wire that runs along side the refrigerant lines. If the condenser is running but not cooling you may want to clean it. This can be done by turning off power to it, then wet it down with a garden hose. Apply a air conditioning coil cleaning solvent to the coil surface. Convenient aerosol spray cans or mixable powder form can be purchased online at HVAC Maintenance & Supplies. (www.mainsupplies.com) Allow the coil to soak for 3-5 minutes then flush out with a garden hose. Be sure the water pressure is not so high that it damages the coil fins. A coil fin tool, also available online at HVAC Maintenance & Supplies can be used to straighten the fins. Repeat this process until the water starts to flush out relatively clear. Safety glasses and rubber gloves should be worn when using coil cleaning chemicals. If your air conditioner is a portable window type you can carefully remove the units outer casing, apply coil cleaner to both evaporator and condenser coils then flush with water. Most dirt will build up on the inside of the condenser coil that can not be seen with out removing the units outer casing. These tips may not resolve all your air conditioning problems but I can tell you that as a service technician myself these are some of the most common problems I have encountered.

Information provided by Terry Manlick with HVAC Maintenance & Supplies. Other maintenance articles as well as hvac maintenance products such as filters, v-belts,humidifier filters and coil cleaners can be found online at www.mainsupplies.com