RTH8500 Wiring O and B Terminals
Please help.
I want to replace an old Honeywell CT3600 thermostat with a new touchscreen RTH8500 on a gas hot air furnace w/AC. I think my confusion is what to do about the O and B wires (changeover HEAT and changeover COOL, as I understand it).
Here is manual for new RTH8500: http://www.honeywellcentral.com/ssi/...-69-1902ES.pdf
Here is manual for old CT3600: http://www.instructionsmanuals.com/u...-CT3697-en.pdf
Terminals used on the old thermostat are RWYGOB. The old thermostat is wired to a Trol-A-Temp MM-2 Mastertrol Mini-Zone-2 at the furnace: http://customer.honeywell.com/techli...0s/69-1361.pdf
Here is a quote from the MM-2 manual:
"The Zone1 thermostat requires a changeover subbase with O and B terminals. The O terminal must make with R when subbase is switched to COOL mode. The B terminal must make with R when subbase is switched to HEAT mode."
After some back-and-forth with Honeywell customer service, they tell me that the RTH8500 will not work for me -- but that was at the end of a 20-minute phone call that started with them telling me that I cannot possibly have my current thermostat (CT3600) wired correctly with both an O an B terminal, so I'm not convinced they gave me good information.
I would like to use either an RTH8500 or a TH8320. Honeywell customer service suggested that I could use a TH4110D1007, but I really don't want that. I asked if there was a touchscreen model that will work with my system and the guy said no.
Can anyone tell me if there is perhaps an appropriate way to wire my system either with an RTH8500 or a TH8320?