Could it be our thermostat?

I went to town and obtained a up-to-date thermostat

It worries myself and others when I don’t suppose how to repair our own appliances. I could find out why our refrigerator was warming instead of cooling. It took myself and others a bit of time to make the repair, however multiple afternoons later, I had a refrigerator that was running as nice as new. When our washer was leaking, I found the manual, obtained the part, and I had a washer that was working perfectly again. I don’t care for it when I can’t find a repair for something I own. I don’t love putting out a lot of money to a repairman that I could have in our pocket. Like last week, when our component broke down. It isn’t love a gas furnace, or some other oil furnace, where there are a lot of complicated parts. I suppose how an component works, and I’m not working with gas or oil. It is an electrical unit. As long as I shut down the power to the A/C unit, it should be easy to labor on. I do all the service on our unit. I shut off the breaker and start working. I can clean the fan and all the other components. I turn the power back on, and it works well again. Last week, I tried to labor on the gas furnace, however it wasn’t working. No matter how much problemshooting I was doing, I wasn’t getting any heat. Then I thought about the thermostat. I went to town and obtained a up-to-date thermostat. I installed according to the instruction. I still don’t have heat and I suppose I need to call the Heating and A/C dealer. Maybe I should have done that in the start.
air duct