This makes sure there really is a problem, and though it sounds silly, it’s the first thing a technician does and you will be charged a service call even if that’s the only problem!
Air coming out of ceiling or floor registers
If no air is coming out, check if the outside unit fan is running. If it is also not running, ensure all the air conditioner breakers are switched on. If the breaker has not tripped, there may be a problem with the thermostat, the air handler/furnace control board or the wires connecting the air handler to the thermostat.
Check if your unit’s condenser pump’s reservoir is not full. If it is, a limit switch usually prevents the air conditioner from functioning. You thus need to have the pump repaired or replaced. If the breaker has tripped, reset it by shutting it off and then turning it back on. Check the wiring in the air handler/furnace for signs of damage and repair if it trips again.
If the outside unit fan is not running, but the blower is, then you need to continue troubleshooting at the outside unit.
Outside unit fan blowing out hot air
There may be a problem with the blower motor, the run capacitor or the air handler/furnace control board if the outside fan is running but not the blower. If the fan motor isn’t running, switch off the power to the unit and check all wire connections for any damage signs like burning or necessary repair. Also check the wire connections in the compressor terminal box and any necessary repair. Check the unit’s capacitors and replace if necessary with the help of the capacitor testing guide.
The troubleshooting continues with turning the unit’s power back on, and observing if the contactor closes or not. Look for a reset button if the unit does not start as the high pressure cutout switch in some units can be reset.
Using a voltmeter, next check if there’s power to the unit and 24 volts reach the contactor’s coil. Check the wiring between the unit and electric panel if there’s no power to the unit. The thermostat and low voltage wires connecting the air handler to the condensing have to be checked if you don’t have 24 volts to the contactor’s coil.
If the unit does not start despite there being power to the contactor’s coil and the unit, the unit’s contactor may be faulty. The condenser fan motor may be faulty if the compressor turns on but not the fan. If the condenser fan starts but not the compressor, it may be because the refrigerant level may be low or the compressor is bad or too hot.
Water around the furnace or ice on the lines connecting the indoor and outdoor units
Check for frost or ice around the units if the furnace blower is running or if there’s water around the furnace. If there is ice on the copper lines going outside, switch off the outside unit for a few hours while the blower on the furnace runs so that the ice melts.
You can continue with the troubleshooting after two hours. Switch the ac back on and after running for five minutes, feel the outdoor unit’s copper line. It should be cold with some condensation on it. If it’s not cold or you find frost forming on the line, it may be a Freon problem. This is when you have to call the repairman as per federal refrigerant usage rules. The troubleshooting at the outside unit can be continued if there is no ice or frost.
If you find that the cooling effect is not enough despite the condenser fan and compressor both running, check the system’s temperature drop. Do this only after the unit has been operating for 10-15 minutes before taking temperature measurements.
The temperature drop can be measured by subtracting the temperature of air leaving the air handler from the temperature of the air entering the air handler. The difference should be about 15 units for high efficiency units and about 18 to 20 degrees for older units with a SEER less than 10. There may be a problem with the refrigerant charge if the temperature drop is much lower than that.
You need to continue with your air conditioner troubleshooting on the system’s air flow if the temperature drop is significantly higher than that. If you find a dirty blower wheel, filter or evaporator coil, it is usually a consequence of not performing regular maintenance on the system.
It may also be triggered by too small a duct system, a result of improper design or installation. The problem can be overcome by increasing the blower’s cooling speed or by replacing the existing blower motor with a variable speed motor.
Need Help With Air Conditioning Repair? Call 262-955-7909 for Fast Service