Came home last night and the a/c didn't work. The thermostat looked like it had no power running to it since the digital screen wasn't lit up. So this afternoon I bought a Honeywell rth2300 and now I'm lost. I hooked red to R green to G yellow to Y white to W and there's a blue one but I'm not sure where it goes. My sons and I are roasting and need help plzzz. I have a trane air handler and trane a/c unit outside