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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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My thermostat says inside 71, and the cool on is flashing

Customer Question

My thermostat says inside 71, and the cool on is flashing and set to 69, but it seems to be blowing hot air
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: I went through the settings again to cool
JA: Do you plan on doing the work yourself?
Customer: i was hoping too
JA: Anything else we should know to help you best?
Customer: its ac/heat unit, and it is only 2 years old i also chsnged the batteries
Submitted: 1 month ago.
Category: HVAC
Expert:  Phil replied 1 month ago.

Hello,I am a retired mechanical engineer with 56 years in this business. I will go in depth with you, and up to a 6 hour time limit.

All I ask is please select the ***RATING LINK*** at the top of your page before leaving, that is the only way I am credited through the site.

Rating does not affect your charges nor ability to refund if not satisfied. If you can agree to that, lets continue by all means.


Is this a central air conditioning system or some other type such as a window unit. If its a central system I need the brand and model number of the outside unit.

We can go from there

Customer: replied 1 month ago.
Central air unit. Lenox. Have to get the model number
Expert:  Phil replied 1 month ago.

If you set most systems for 69F cooling and let it run at night when it is also cool outside, the cooling coil will ice and block most of the air flow... does it seem like the air flow is reduced? Is the outside unit running or not running. Is the largest tube connected to the unit outside frosty or iced?