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Only have two wires. Red and white. Relay at boiler has two existing wires hooked to indicators T and T. Which connection would I use in this system to add the c or constant. Following are locations I have L1 L2 C1 C2 Zc zr b1 b2 and the two T's

the new thermostat Calls for a common and I can get power to it but what I have to do removes the white which I think turns the heat on when system calls for it.

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You're going to need an extra wire between the boiler and the thermostat. You'll also want to check the schematic to determine where to connect the wire. Including the make and model of the boiler would allow folks to search for the schematic themselves. –  Tester101 Feb 9 '14 at 16:35

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