After seeing all the exciting forum posts about wireless thermostats, I finally bought a Honeywell thermostat . I have a 2006 model RHEEM gas furnace with air conditioning unit connected to a 3 Zone Honeywell EMM-3 controller board with 3 programmable thermostats. Four wires from Rheem furnace board go into the Honeywell. When I opened the Honeywell EMM-3, it has only input for the 4 wires excluding the BLUE. But the 3 Zone outputs at the bottom of the controller has a place for C wire in all the zones.
My question is, if I just plug in the blue wire on to the EMM-3 and connect the other end to the Honeywell thermostat, will it work? If so, how come the EMM-3 zone controller provides output for C with out getting any input from the furnace? How do I check before connecting anything to it? I do have a multi meter. Any comment from the experienced forum members would be very helpful. I have attached the zone controller picture down below. Input from furnace is on top left and the 3 Zone outputs are at the bottom. Thanks for all the help.
RHEEM furnace --4 wires --> Honeywell EMM-3 --> 4 wires to thermostat (Blue wire in the bundle is just rolled up in all the places)