I had been reading that digital thermostats will aid in decreasing your electric costs and allow you to be more energy efficient. I did some reading about 5 day, 5 -1-1, 5-2, and 7 day programmable thermostats. I selected the Honeywell RTH2510B because it was the same price as many of the others but offered a 7 day programmable schedule. Each day allows me to program 4 different temperatures into it. I purchased this to replace a mercury Trane thermostat. I am running an electric and gas heater with auxiliary heat pump and backup heat. I have 8 wires on my unit. They are labeled to Texas code. B, O, G, Y, W, W2, T, R. I read through the directions and followed them closely. I turned off the circuit breakers for the outdoor compressor/unit and the intake unit in the AC closet. Next I labeled the wires with the included labels B, O, G, Y, W, W2, T, R and disconnected them. I had to be very careful when pulling the wires through the old thermostat because the labels were getting snagged. I removed the old thermostat and lined up the Honeywell RTH2510B over the wires and it neatly covered the pre-existing holes. The holes did not line up with the Trane thermostat and I had to mark, drill holes, anchor, and screw the back plate of the Thermostat in place. I used a leveler to verify it was level. Next I installed each wire on the appropriate block. The wire block is labeled as B, O, G, Y, w/Aux, Not Used, R, RC. After I finished wiring it up I had W2 and T dangling and not connected. In the next section of the book it talks about not using B and W2 and C. I began to flip through the book looking for a wiring diagram. I did not locate one. Then I looked online. I was starting to sweat as I looked for the correct wiring diagram. I was about reading to plug in the breakers and turn on the AC then I came across the Honeywell customer service number which stated to call with technical questions. I called up Honeywell and after about a 5 minute hold a male with a thick accent asked me questions about my AC unit and the old thermostat. He concluded (Because I was not aware of it) that I have the AC with Aux Heat pump and backup heat. He explained to me that on my old thermostat I was able to manually turn on the backup heat but the new one does it automatically. He also explained that there was no way for the thermostat to tell the difference between the regular heat and backup heat setting. When I asked him to explain the differences he basically said it was my backup heat if the my heat stops working and interjected that the heat pump will still function regardless after we do some programming and re-wiring at the thermostat. He asked if I still wanted to continue. I told him yes. He had be disconnect B and T and wire O to O, G to G, Y to Y, W and W2 to w/AUX, R to R and RC. Then on the thermostat had be program the setting for 1-0 to 1-1 and 5-5 to 5-6. Then told me that I would need to turn on the breakers and everything should work. We got off the phone and I went back and turned on the breakers. I turned the AC without and issues. I turned it off then set it to heat and nothing happened. Heat On just flashed at me. I got a bit concerned and called Honeywell back. The next person I got on the phone had a heavy accent that was harder for me to understand than the first person; however, this person explained to me that there is a failsafe mechanism on the Honeywell RTH2510B that delays turning on the AC or Heat when initially switched from Heat Off Cool that lasted 5 minutes. This occurs when the user sees Heat On or Cool On the display flashing. This prevents the thermostat from burning out the heat pump. Once five minutes had passed the Heat or AC would turn on and the Heat On or Cool On the display will be solid. She stayed on the phone with me as I tested this function out. Everything worked fine. The manuals that come with this are the quick installation guide and the operating manual. They both are rather thick and pretty intimidating at first glance. However, after reading them while at the thermostat I was able to quickly learn how to program the thermostat in about 5 minutes. I am not sure if not having the ability to manually turn on my backup heat vs letting the thermostat do it an issue. I was assured that it should not be. However, with that said, if I was aware that I have backup heat I would probably have spent more money for a digital thermostat that accommodated manually turning it on because that was a feature on the original thermostat. I could have sent this one back but since I was told it did not cause issues I felt I would be wasting money in the return shipping. I will continue to use this one and do some more research on the backup heat and manual setting. I would recommend this product. It is easy to install. The directions are easy to understand and is very easy to use. There is free tech support to walk you through the install if you have any questions whatsoever. It is made for gas/oil and electric units. It is not made for manual selection of backup heat but will function with it through wiring and additional programming.
