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HomeRepair HelpTappan Central A/C RepairTappan Central air conditioner won't turn on Repair
Tappan Central air conditioner won't turn on
If your Tappan central air conditioner won't turn on, start with the transformer, the most likely cause. The furnace or air handler transformer supplies the 24-volt signal that lets the wall thermostat energize the contactor and start the outdoor condensing unit. A failed control board is the next likely cause, especially when the contactor is not receiving 24 volts or the furnace blower motor has no power. If the thermostat display is blank, replace its batteries, then check incoming power to the furnace or air handler, including the circuit breaker, fuse, and unit power switch. A defective wall thermostat or thermostat wiring is less common, but either can stop the cooling signal from reaching the contactor through the thermostat wire. This troubleshooting applies when an air conditioner is not turning on, the AC unit is not turning on, or the central air conditioner won't start. Replacing thermostat batteries is generally safe for a DIYer. Testing 24-volt circuits requires care, while checking the disconnect box, circuit breaker, transformer, control board, or other line-voltage components should be handled by a qualified technician. Enter your model number to find the exact replacement part for your Tappan central air conditioner.
01 - Tappan 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 - Tappan 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 - Tappan 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 - Tappan 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 Tappan central air conditioner not turning on?
What should I check when my AC thermostat is not turning on the air conditioner?
How do I test the transformer or control board when my AC will not start?
Could a tripped breaker, fuse, or disconnect keep the Tappan outdoor AC unit from turning on?
How can I find the correct Tappan AC replacement part for my repair?
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