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HomeRepair HelpPhilco Central A/C RepairPhilco Central air conditioner won't turn off Repair

Philco Central air conditioner won't turn off

If your Philco central air conditioner won't turn off, a shorted contactor or a bad wall thermostat or thermostat wiring is the most likely cause, keeping a cooling signal on the yellow (Y) terminal even after the thermostat is set to Off. A shorted furnace control board or main control board can cause the same problem, though it is a less common cause, by continuing to send voltage to the outdoor condensing unit and making the air conditioner run constantly. A shorted furnace control board can continuously send voltage to the outdoor condensing unit, keeping the compressor and condenser fan running. The main control board can fail in the same way and should be inspected for visible damage. Next, check the wall thermostat or thermostat wiring. A thermostat contact that sticks closed can keep sending a signal through the yellow, or "Y," thermostat wire to the control board and contactor, even when the thermostat is set to Off. A defective thermostat may show continuity between the "C" and "Y" terminals while off. Less commonly, a shorted contactor can keep supplying power to the condensing unit. This repair involves electrical testing, and the contactor and other outdoor components use hazardous 240V line voltage, so have a qualified HVAC technician handle that work. Enter your Philco central air conditioner model number to find the exact replacement control board, thermostat, or contactor for your system.

01 - Philco Central Air Conditioner Control Board

If the furnace control board has a short, it may be providing continuous voltage to the central air condensing unit preventing it from turning off. Inspect the control board for any damage and replace if necessary.
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Common

02 - Philco Central Air Conditioner Main Control Board

If the furnace's main control board has a short, it may be providing continuous voltage to the central air condensing unit preventing it from turning off. Inspect the control board for any damage and replace if necessary.
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Common

03 - Philco Central Air Conditioner Wall Thermostat

The wall thermostat has electrical contacts that send signal voltage back to the control board and the condensing unit's contactor to run the central air system. If the contact that controls the contactor sticks closed, it will send continuous voltage to the contactor, causing the central air system to run continuously. To determine if the thermostat is defective, use a multi-meter to test it for continuity. If the wall thermostat shows continuity between the common (“C”) and yellow (“Y”) thermostat wire terminals when the thermostat is in the off position, the thermostat has failed and will need to be replaced.
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Common

04 - Philco Central Air Conditioner Wifi Thermostat

The WiFi thermostat has electrical contacts that send signal voltage back to the control board and the condensing unit's contactor to run the central air system. If the contact that controls the contactor sticks closed, it will send continuous voltage to the contactor, causing the central air system to run continuously. To determine if the thermostat is defective, use a multi-meter to test it for continuity. If the WiFi thermostat shows continuity between the common (“C”) and yellow (“Y”) thermostat wire terminals when the thermostat is in the off position, the thermostat has failed and will need to be replaced.
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Common

05 - Philco Central Air Conditioner Contactor

The furnace control board sends a low voltage signal to the contactor. When the contactor receives the signal from the control board, it closes the circuit, sending voltage to the condensing unit components. If the contactor has shorted, it can send continuous voltage to the condensing unit's components resulting in the central air system not turning off. To determine if the contactor is at fault, use a multimeter to test the contactor for a short. If the contactor has shorted, replace it.
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Less Common

Frequently Asked Questions

Why won't my Philco central air conditioner turn off?
How do I test a thermostat when my central air won't turn off?
Can a bad contactor cause an air conditioner to run constantly?
Could a Philco control board be keeping the AC from shutting off?
How do I find the correct Philco replacement part for a central air conditioner that won't turn off?

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