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Install & Replace

Selecting the right programmable thermostat

I am replacing my thermostat and I'd like to replace it with the programmable type.  I first purchase a Honeywell RTH2300.  When I got it home I realized it was not compatible with my system.  I have a gas furnace and central AC.  Next I tried a Honeywell RTH2510B.  It still does not seem compatible.  The terminals on my furnace are labelled

Y1, Y/Y2, W, R, G and C.  The thermosat terminals are O/B, Y, R, G and W/AUX.  Can someone tell me which Honeywell programmable thermostat is compatible?

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Posted 2011-01-06T11:05:10+0000  by tigerlily1962 tigerlily1962

Greetings and welcome to our community,


Thermostats can be quite confusing as there are several options to choose from and many different wiring configurations.


I spoke to Honeywell and have good news. The RTH 2510B will work and should be wired as follows;

Y-1 to Y, W to W/aux, R to R, G to G. The Y/Y2 and C likely need not be used. If you have any questions they would love to speak with you at Honeywell Customer Care call 877-271-8620.


We are happy to help and again thank you for using the resources available through



Posted 2011-01-06T14:31:51+0000  by HD116
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