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HomeRepair HelpYork Central A/C RepairYork Central air conditioner won't turn on Repair
York Central air conditioner won't turn on
If your York central air conditioner won't turn on, the most likely cause is a failed transformer, which supplies the 24-volt signal from the furnace control board to the thermostat and contactor. A defective control board can also prevent the condensing unit or furnace blower motor from receiving the required signal. Next, check the wall thermostat batteries if the display is blank, then verify incoming power, including the furnace or air handler disconnect, circuit breaker, and fuse. If power is present but your air conditioner is not turning on, a faulty wall thermostat or thermostat wiring may not be sending 24 volts between the C and Y thermostat wire terminals. Testing low-voltage circuits with a multimeter can help identify the problem, but work inside the furnace, air handler, or outdoor condensing unit may involve dangerous 240-volt power. Turn off power before inspection, and have a qualified HVAC technician handle line-voltage diagnosis or repairs beyond your experience. Refrigerant service is not part of this symptom, but any sealed-system work requires EPA 608 certification. Enter your York model number to find the exact replacement transformer, control board, thermostat, or other part for your specific central air conditioner.
01 - York Central Air Conditioner Transformer
The furnace control board sends a low voltage signal of 24 volts to the thermostat. When the themostat cooling contacts close, a 24 volt signal is sent to the contactor coil, closing the high voltage circuit and sending power to the condensing unit components. Some furnaces have a separate transformer for the 24 volt circuit, so if the contactor is not receiving the proper voltage when the thermostat cooling contacts are closed, it's likely this transformer has failed and the component will need to be replaced.
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Highly Likely
02 - York Central Air Conditioner Control Board
If the central air condensing unit contactor is not receiving 24 volts or power is not getting to the furnace blower motor, a possible cause is a defective furnace control board. While this is not a common problem, if all other potentially faulty components are working properly, the control board should be replaced.
Highly Likely
03 - Wall Thermostat Batteries
Most wall thermostats are either powered by an enclosed battery or by the furnace or air handler transformer. If the thermostat display is dead, you can remove the thermostat cover and look for replaceable batteries. Replace the batteries if needed and check operation.
Common
04 - Incoming Power Problem
Check to see if there is power to the furnace or air handler. One or more indicator lights on the control board should be illuminated. If there is no power to the furnace or air handler, check to see if a circuit breaker has tripped or a fuse has blown. Confirm the power switch on the side of the unit is turned on.
Common
05 - York Central Air Conditioner Wall Thermostat
The furnace control board sends a low voltage signal of 24 volts to the contactor through the wall thermostat. When the contactor receives the signal from the wall thermostat, it closes the circuit, sending voltage to the condensing unit components. There should be 24 volts between the common (“C”) and yellow (“Y”) thermostat wire terminals on the furnace control board when the wall thermostat is in the cooling mode. You can check for this voltage with a multimeter. If voltage is not reaching the contactor, it's likely the wall thermostat is defective and will need to be replaced.
Less Common
06 - York Central Air Conditioner Wifi Thermostat
The furnace control board sends a low voltage signal of 24 volts to the contactor through the WiFi thermostat. When the contactor receives the signal from the WiFi thermostat, it closes the circuit, sending voltage to the condensing unit components. There should be 24 volts between the common (“C”) and yellow (“Y”) thermostat wire terminals on the furnace control board when the WiFi thermostat is in the cooling mode. You can check for this voltage with a multimeter. If voltage is not reaching the contactor, it's likely the WiFi thermostat is defective and will need to be replaced.
Less Common
Frequently Asked Questions
Why is my York central air conditioner not turning on?
How do I know if the thermostat is causing my central air conditioner not to start?
What should I check when the outdoor AC unit is not running but the thermostat works?
Could a failed transformer or control board keep my York AC from turning on?
How do I find the correct York central air conditioner replacement part?
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