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HomeRepair HelpHeil Central A/C RepairHeil Central air conditioner won't turn on Repair
Heil Central air conditioner won't turn on
Won’t your Heil central air conditioner turn on? Start with the 24-volt control circuit before replacing major parts. The most likely causes are a failed transformer or furnace control board, which can prevent the contactor from receiving the signal needed to power the outdoor condensing unit. A dead thermostat display may simply need new wall thermostat batteries. Next, check for an incoming power problem, including a tripped circuit breaker, blown fuse, or furnace or air handler power switch that is turned off. If the thermostat is calling for cooling but the contactor still receives no 24 volts, the wall thermostat, wall thermostat, or thermostat wire may be defective. Testing voltage at the control board and contactor requires care, and work around the furnace, air handler, disconnect box, or outdoor unit can involve dangerous 240-volt power. Shut off power before inspecting anything, and have a qualified technician handle line-voltage testing or repairs beyond your comfort level. Refrigerant service is not indicated for this symptom, but any sealed-system work requires an EPA 608-certified technician. Enter your Heil model number to find the exact replacement transformer, control board, thermostat, or other part for your central air conditioner.
01 - Heil 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 - Heil 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 - Heil 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 - Heil 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 Heil central air conditioner not turning on?
What should I check if my AC thermostat is not turning on the air conditioner?
How do I test the transformer or contactor when my central AC will not start?
Could a bad furnace control board keep my Heil AC from turning on?
How do I find the correct Heil central air conditioner replacement part?
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