Dear all, how are you doing?
Did some research before posting here, as I think my question is sort of specific to my thermostat model and condition. The current thermostat looks REALLY OLD, and here are all the info that I could find (from the back of the cover) for this OLD thermostat:
==========================================
Brand: General Controls Thermostat
Catalog No. T94A104 (not sure if this is the model#)
Serial No. A0
For use with low voltage circuit only
==========================================
Here is a photo taken from my cell phone:

As you could see the colors of all the wires are off, so I can't really tell which wire is for what function. The heater/furnace is a fairly new one (maybe 10 - 15 years old, the model is Bryant 90 Plus). Our current problem is that the preset thermostat seems to be not so precise. For example, if we set the temperature on the thermostat to be 65 degree, most of times it will overshoot and the room will be heated up to around 70 - 72 degree before the furnace shut down (by the thermostat I presume). I feel that the problem is on the thermostat, as it seems to be still using some sort of old mechanism (springs, etc.) to determine indoor temperature. Here are my questions:
I'm thinking that if I can NOT DIY, maybe I could purchase the thermostat from amazon first, then hire my contractor friend to help out replacing it. But I want to make sure that it would work with my existing wiring and existing furnace. Any help, suggestion, comments, or feedback would be highly appreciated. Thanks again!
Did some research before posting here, as I think my question is sort of specific to my thermostat model and condition. The current thermostat looks REALLY OLD, and here are all the info that I could find (from the back of the cover) for this OLD thermostat:
==========================================
Brand: General Controls Thermostat
Catalog No. T94A104 (not sure if this is the model#)
Serial No. A0
For use with low voltage circuit only
==========================================
Here is a photo taken from my cell phone:

As you could see the colors of all the wires are off, so I can't really tell which wire is for what function. The heater/furnace is a fairly new one (maybe 10 - 15 years old, the model is Bryant 90 Plus). Our current problem is that the preset thermostat seems to be not so precise. For example, if we set the temperature on the thermostat to be 65 degree, most of times it will overshoot and the room will be heated up to around 70 - 72 degree before the furnace shut down (by the thermostat I presume). I feel that the problem is on the thermostat, as it seems to be still using some sort of old mechanism (springs, etc.) to determine indoor temperature. Here are my questions:
- Is my guess correct that the problem is caused by thermostat?
- Giving my current condition and existing wiring (don't want to rewire again), is it possible for me to replace the old one with a modern thermostat, such as this amazon one (Lux Products TX1500), see http://www.amazon.com/Lux-Products-TX1500E-010-Programmable-Thermostat/dp/B001C0G4O8/
- Does this seem to be a DIY job, or do I have to hire a professional to do this? What tools do I need to figure out which wire is for what purposes?
I'm thinking that if I can NOT DIY, maybe I could purchase the thermostat from amazon first, then hire my contractor friend to help out replacing it. But I want to make sure that it would work with my existing wiring and existing furnace. Any help, suggestion, comments, or feedback would be highly appreciated. Thanks again!