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I have a new Home with a Lennox 51M34 ComfortSense 3000

Customer Question
I have a new...

I have a new Home with a Lennox 51M34 ComfortSense 3000 Series Model L3511C thermostat - works fine but the internal light on the Thermostat has never worked? Is there a way to check it or repair just the light? Skot

Contractor's Assistant: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?

Just something specific to the thermostat? Every thing else seems to work fine

Contractor's Assistant: Do you plan on doing the work yourself?

Yes

Contractor's Assistant: Anything else we should know to help you best?

Nothing I can think of?

Submitted: 7 months ago.Category: HVAC
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Answered in 3 minutes by:
12/19/2017
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 7 months ago
BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 23,122
Experience: Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
Verified

Hello,

My name is Billy. Can you tell me if the thermostat wiring has a C terminal with a wire in it?

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Customer reply replied 7 months ago
it is a black wire
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 7 months ago

And when you press any button for function, the back light does NOT engage?

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Customer reply replied 7 months ago
Correct no light engaged at any time
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 7 months ago

Unfortunately there is no menu option to able/disable and the light is a function that engages whenever any button is pressed. If yours is not lighting then there is an internal defect. This cannot be field repaired.

I hate delivering what I call nonsense answers.....but the thermostat would have to be replaced to get this feature working.

I am very sorry but there is no work around for this on this model.

Billy

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Customer reply replied 7 months ago
Thanks that is what I figured...there is no in the L terminal?
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 7 months ago

The L terminal would be for a alarm or light. Some units like heat pumps illuminate a red light while in emergency heat.

The L terminal is for a light but external the thermostat

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Customer reply replied 7 months ago
Cool I will see if I can get the Builder to replace the whole Thermostat since the home is not very old
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 7 months ago

Thank you for your patience and I wish you the best. If any other questions please let me know.

Billy

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