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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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My lennox value series furnace has a blinking light,

Customer Question

Hello my lennox value series furnace has a green blinking light, thermostat is recognizing cool and fan but once I push heat nothing happens
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.


The furnace is off on one if its safety devices, high limit, pressure switch failed flame sensing or flame roll out most likely... if it is an older furnace the printed circuit board. or inducer fan may be bad.

Please attach a well focused, close up photo of the wiring diagram glued inside the service panel, the picture needs to be taken from straight on, in very good light.

You can use the paper clip- icon at the right end of the tool bar at the top of this dialog box to attach it here.,Include a picture of the thermostat wire connections to the printed circuit board in the same area.

If you have an error code showing, tell me what the code read out is on the wiring diagram or a sticker next to the diagram please.

If there is no paper clip-icon, look for the '+attachfiles'link at left of your send button.

I can mark it up with trouble shooting instructions.

We can go from there.

Customer: replied 1 year ago.
Where would the wiring diagram be?
Expert:  Phil replied 1 year ago.

The diagram is a 10 x 12" sheet of paper glued to the inside of the blower service panel... you must first locate the blower compartment, then remove its door.. then you will see the wiring diagram

If your furnace is an upflow type the blower compartment will be the one nearest the floor. the blower door will lift up 1 inch or so then pull out at the top you will see the blower inside.

Expert:  Phil replied 1 year ago.

If you have trouble with that, send me a photo of the furnace taken from 15 feet away, I will point out the blower compartment.

Customer: replied 1 year ago.
Will this suffice?
Customer: replied 1 year ago.
Expert:  Phil replied 1 year ago.

Hello again

take pictures of the printed circuit board while you are there, I need to see the whole board, including the thermostat wire connections.

Customer: replied 1 year ago.
How do you take off the door its sealed right?
Expert:  Phil replied 1 year ago.

Look for screws on either end of the door... or along the bottom. but not more than 4 screws in total, then slide the door to the left an inch and pull it out.

Customer: replied 1 year ago.
Is this it?
Expert:  Phil replied 1 year ago.

Hello again, thats part of it, but it needs to be taken from straight on, or as in this case the left side blurs out of focus.

Expert:  Phil replied 1 year ago.

That is an error code list, which I can use, but it is not the wiring diagram with a whole lot of skinny lines on it.

Customer: replied 1 year ago.
Here's the exact one
Customer: replied 1 year ago.
Will that work?
Expert:  Phil replied 1 year ago.

Thanks, ***** *****

Let me know what you find, we can go from there.