“How can I determine if I have the "C" wire? Do I have to remove the existing thermostat?”
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You will need to remove your old thermostat to determine if you have a C wire. Just because it's there don't assume it's real. You will need your system powered on to test. You need to CAREFULLY, using a volt meter set on AC, measure the voltage between the R ( could be RC in some cases) wire and the C wire. You should see 24 Vac. It could be as high as 29 Vac when nothing is running, and nothing will be with your thermostat removed. If you have the voltage then the C wire is real and you can continue. If not consider having your system updated to include it.
Sorry, there was a problem. Please try again later.Yes. Just pop the existing stat off of the base and look and see what wires you currently have. If there is a wire on the screw or lug marked C, then you have one.
Sorry, there was a problem. Please try again later.Remove the thermostat. Look at the connections. Many have labels near them. R, C, W, Y, G, etc. C is what you want to look for.
Sorry, there was a problem. Please try again later.Yes, check your existing unit wire layout. Most order systems don't but check your labeling.
Sorry, there was a problem. Please try again later.Easiest way to check is pull any batteries out of the old thermostat and look for a wire (normally blue) is connected to the C spot. If the old unit supports being powered by the common wire, then the unit will turn on without batteries. This will not work if the old thermostat requires batteries and a connection to the C spot.
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