Guys, Thanks so much so far. I'm beginning to understand it more but I'm still out in left field. My Trane TAYSTAT540 Thermostat: B - blue Y - yellow (compressor contractor 1) G - green (fan) O - orange (switchover valve) X2 - black (em. ht. relay) W - white (aux heat relay) R - red F - (defrost controller) Wires to the Transformer (from thermostat): Blue wire in on R ( Green wrie is on G Yellow wire is on Y Red & White got to motor Wire from A/C unit to transformer: White is on com Red is on Y Obviously matching colors isn't working, assuming my A/C is functioning. I need help placing the correct wire on the thermostat. Thanks so much for the so far.

Thanks for all the support Dave. The installer just left having completed the job. In the end we decided to take your advice and install a remote temp sensor in the media room to relay the temp in that area. This should help to neutralize the significant heat output of the projector and keep the HT room cooler. I now have an extra SYSTXBBUIZ01 controller that needs to find a new home. I just discovered that the main furnace in living room is a 315A too and is currently wired to a Thermidistat via the std pins on the furnace. Am I losing any benefits by not using a communicating controller via the 4 pin green connector? Is there any reason why I can't wire this Z01 (zone) evolution controller up to the furnace directly? The manual shows it should be wired into a damper system but I don;t see why it can't go directly to the furnace.

Sounds as if you have a single stage cooling and heating. Y is connected to Y. According to your colors, this is blue. G is connected to G. According to your colors, this is green. W is connected to W1. According to your colors, this is white, though you seem to have two whites. Hopefully you marked which is which when you took them off the old thermostat. R is connected to R. According to your colors, this is red. This is the 'hot' or +24v power wire. C on the furnace goes to C. I guess you configure the 'stat for 'conventional' operation, in your case AC and gas.

Pressure balance is what you want I can’t see a thermostat being good in a guest shower and if you kids are too young to set the water temp they pobably should not be in there alone.You could get these I use them in my guest bath for my grand kids at the sink for washing hands and brushing teeth. The lights tell them when the temp. is right that is when it is green I haven’t need the tub and shower yet.