I have a Trane BAY28X139/141 mercury thermostat with heat pump. I called Honeywell help line and they recommended RTH3100 or RTH2510 model. I need help to connect it properly. Current 8 wires system: R - Red T - Gray O - Orange G - Green Y - Yellow X2 - Black B - Blue W - White If someone could help me, I´ll appreciated it.

Speaking specifically about the Ecobee and Nest it appears that multiple thermostats need to be purchased. Here is the situation. I have a 2 zone hot water system. Each zone has a separate hard wired thermostats to control the circulator for that zone. Thus, in order to call for heat, you must go to the thermostat that covers the area you want to heat and turn it up. This energizes the circulator pump and heats that zone. Now if I want to switch to a smart thermostat it would appear that a separate one needs to be purchased for each zone. Does anyone know of a SINGLE thermostat that can be wired or remotely monitor another zone and turn that on when needed? Ecobee says you need a separate unit for each zone but to be perfectly honest, I would rather rely on the knowledgeable people here rather than the customer service people who seem asleep at the wheel while I am speaking to them. So, any ideas how this can be done with single thermostat? Thanks Ray