Room size 100 Sq. Ft. needs split unit AC be installed. Condenser unit cannot be installed on top of room, but far away on the roof top of the building, some 70 - 80 ft away. One tech guy came to inspect location, said it would need a unit of 24,000 BTU ! Isn't that too much for such small room. He reasoned, if unit (condenser) was on top of room, no problem, be way smaller unit. Yet as it will have to be located far away, and for better cooling, especially when in hot desert-like climate, no less than 24K BTU, should be installed. Any thoughts, input, folks with expertise in split unit AC. Thanks.

Hello! I have an old central AC unit that cools the house but has to be switched on and off from the breaker. As soon as the breaker is switched on, regardless of whether the thermostat is set to heat, cool or off, the condenser comes on. The only way to turn it off is by switching it off again at the breaker. It appears to be wired to the furnace and those wires are then connected to the thermostat, but it just seems to not be "speaking" to the condenser. I've included pictures of the furnace control board and the thermostat wiring. The furnace is a Lennox Elite Series. Thanks for any help you can provide. [img]https://cimg0.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/img_20200629_164231230_89e0cdca4af3091d25206a679350f98cad16ac5e.jpg[/img] [i]Lennox Control Board[/i] [img]https://cimg3.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1130/wp_20191007_19_04_24_pro_81b6f1d3dc7fdc53ebe7608a5a93d3a1d65d353c.jpg[/img] [i]Noma thermostat[/i] [img]https://cimg6.ibsrv.net/gimg/www.doityourselft.com-vbulletin/1500x2000/img_20200629_164305174_891749a384d14e31955d3216a393855db2d7fd29.jpg[/img] [i]Lennox wiring diagram: one thing I do notice here is there appears to be a common wire that runs from the control board to the thermostat that my system does not have. Not sure if that's part of the problem.[/i]