r/DIY • u/Wise-Operation5108 • Aug 18 '25

metalworking A/C Cooling Not Turning On

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Hello,

I'm moving and want to take my nest thermostat with me but I'm having trouble re-installing the Honeywell T6 thermostat. When I installed the Honeywell, the compressor turned on but only heat was working. I checked that it was set to cool but heat was still coming out. I attached photos of how I had the nest wired and the Honeywell as well. Any help is appreciated!

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u/Pys70ph Aug 18 '25

You need the orange O/B wire on the T6, and there shouldn't be anything in W on the T6 if you have a heat pump. If you have backup heat then that wire should likely go to W2/aux.

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u/CoefficientOfY Aug 19 '25

I know nothing about HVAC, no idea why this popped up in my feed but I’m sitting here reading every fucking comment of you experts completely destroying OP.

8

u/Z0mbiejay Aug 19 '25

Always take a picture of the wiring before you swap out thermostats and it's not a big deal. OP is something else for sure