Nothing is worse on a hot summer day than an air conditioner that isn’t working properly. Here are some troubleshooting tips to try.
The first step is to turn the thermostat lower than room temperature to ensure there really is a problem.
Is there air coming out of the floor or ceiling registers?
If there is no air, check to see if the outside unit’s fan is running. If it isn’t running either, make sure that the breakers for the furnace/air handler and the air conditioner are on. If the breaker isn’t tripped, the problem may be the thermostat, the control board, or the wires between the furnace/air handler and the thermostat. If it is tripped, shut it off and back on, and if it trips again, the wiring may need to be repaired.
You should also make sure the reservoir on your condensation pump (if you have one) is not full. If it is full, you will need to repair or replace the pump.
Is there ice on the lines connecting the indoor and outdoor units?
If there is ice on the copper lines going outside, shut off the outside unit for a couple hours but leave the furnace blower run – this will melt the ice.
After waiting a couple hours, turn the AC back on and let it run for around five minutes, then feel the larger copper line at the outdoor unit. It should feel cold and have condensation on it. If it is not cold or if there is frost forming, it is probably a problem that will need professional repair.
Is the unit providing cooling but not enough?
If both the condenser fan and compressor are running but aren’t producing adequate cooling, check the temperature drop of the system (the system should be running at least 10-15 minutes before testing temperatures). To measure the temperature drop, measure the air temperature leaving the air handler and subtract it from the temperature of the air entering the air handler. The result should be about 15 degrees for a high efficiency unit and about 18 to 20 degrees for an older unit. If the temperature drop is significantly less, the refrigerant charge may be the problem.
If the drop is significantly higher, then troubleshooting should focus on the system’s air flow. The evaporator coil, filter or blower wheel may be dirty, which results from improper maintenance. It may also be caused by a insufficient duct system.
If you find a problem with your air conditioning system and cannot diagnose the problem, call Heatmasters. We specialize in emergency A/C service, so you don’t have to live with a broken system for long!
Courtesy of HVAC for Beginners
http://www.hvac-for-beginners.com/air-conditioner-troubleshooting.html
