Just bought a Trane and opened up the old thermo and there is only 2 wires?

[chowda633]

After doing a bunch of reading looks like this 2 wire line coming into the old thermostat is a battery operated setup. In order too use the Trane I would need to re run a 5 wire line through the wall too it? Never messed with HVAC before. I have 2 zones in the house though. One for upstairs and one for the inlaw apartment. Figure I can use the Trane in the garage if needed. (1200 sqft outbuilding garage gas heat). What are my options here?

Thanks!
Josh

[TC1]

[quote=“chowda633, post:1, topic:178409”]After doing a bunch of reading looks like this 2 wire line coming into the old thermostat is a battery operated setup. In order too use the Trane I would need to re run a 5 wire line through the wall too it? Never messed with HVAC before. I have 2 zones in the house though. One for upstairs and one for the inlaw apartment. Figure I can use the Trane in the garage if needed. (1200 sqft outbuilding garage gas heat). What are my options here?

Thanks!
Josh[/quote]

I suspect since you only have two wires, then your thermostat controls just your heat, or you have a manual changeover switch (heat to A/C) somewhere else. If that is the case, then you only need one more wire in order to power the thermostat from the HVAC unit you have. I ran into the same situation, electricians are rewiring my house (due to Sandy) and they simply replaced the two wire thermostat control that was there already. Told them I needed a Common wire connection so I could use an internet enabled thermostat down the road. They pulled a new three-wire run and hooked the third wire to the common connection on the zone transformer/relay box.

Hope this helps,

-TC