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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I recently changed my thermostat and now the AC unit will

Customer Question

I recently changed my thermostat and now the AC unit will not turn on at all. The LED light on the furnace is also not coming on. Both thermostats (1 upstairs and 1 downstairs) are on and light up. I'm not sure what to do.
JA: Thanks. Can you give me any more details about your issue?
Customer: No
JA: OK got it. Last thing — HVAC Technicians generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: HVAC
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  BillyHvac replied 1 year ago.


My name is Billy.

Is your furnace new enough to where it has a small automotive type fuse on the circuit board?

Customer: replied 1 year ago.
It's a Carrier brand furnace and we followed the wires back to the damper system...we aren't sure how to get past the damper system to look at the circuit board.
Expert:  BillyHvac replied 1 year ago.

Thank you know where your zone control box is where the thermostats wire into? And then the zone panel sends wire to the blower section of furnace?

Customer: replied 1 year ago.
I know where they are. How do I get into it?
Expert:  Phil replied 1 year ago.

Hello, use the paper clip icon at the right end of the tool bar to send me some photo's of zone control box... normally there is either latch or 2 screws that hold the cover on... there will a wire cable from each thermostat going into the box, and a wire for each of two dampers going out of the box, and another wire going to the furnace or air handler.

If you can locate the furnace or air handler, remove the blower door, and take a photo of the printed circuit card inside. well lit and well focused, I can point out any fuses that might be blown.