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Error code reference

Lennox Air Conditioner Error Code 14

Control is in TEST mode; does not indicate a problem.

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What the 14 error code actually means

Error code 14 on your Lennox air conditioner just means the system is running in a special test mode used by technicians during installation or service. It does not mean anything is broken or wrong with your unit. If you are seeing this code unexpectedly, it may have been accidentally turned on and can be cleared by exiting test mode or resetting the system.

Diagnostic procedure

The full 14 procedure

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1
Confirm the fault
Power cycle the unit: switch off the breaker for 60 seconds, then restore power. If the code returns, the fault is persistent and the procedure below isolates the cause.
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Most common causes of 14

Ranked by how often they cause this code
  1. 1Intentional activation during service
  2. 2Accidental activation via control interface
  3. 3TEST mode not properly exited after diagnostics
  4. 4Control board retaining TEST mode state after power interruption

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Questions people ask about 14

What does 14 mean on a Lennox air_conditioner?
Code 14 on a Lennox air conditioner means the control board is in TEST mode. This is a built-in diagnostic function used by technicians during installation or servicing. It does not indicate any fault or problem with the system. The code will typically clear once TEST mode is exited or the unit is power cycled.
Is error code 14 on a Lennox air conditioner dangerous?
No, code 14 is not a safety concern. It simply means the unit is in a diagnostic TEST mode and is not a sign of any electrical, mechanical, or refrigerant issue. Your system is not at risk while this code is displayed.
Does error code 14 on a Lennox air conditioner require a costly repair?
No parts or repairs are needed to resolve code 14. Since it only reflects TEST mode being active, there is no cost associated with clearing it beyond a potential service call fee in the range of 75 to 150 dollars if you need a technician to come out and exit TEST mode on your behalf.
How do I fix error code 14 on my Lennox air conditioner?
Because code 14 is not a fault, no repair is needed. You can clear it by exiting TEST mode through the control interface or by cycling power to the unit at the disconnect switch. If the code returns repeatedly without any technician activity, contact a qualified HVAC technician to review the control board settings.
Will resetting my Lennox air conditioner clear error code 14?
Yes, a power reset will generally clear code 14. Turn off the unit at the thermostat, then switch off the disconnect or breaker for at least 30 seconds before restoring power. If the code reappears after reset, TEST mode may have been re-activated through the control interface.

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