I am trying to determine exact wiring from my ancient honeywell thermostat so that I may properly wire my new one. My original thermostat is a Honeywell Chromotherm890121. The terminals are X, W3, W2, O, R, B, G, E, Y, L. I have a red, black, blue orange, yellow, green, white, and a brown which was not being used. everything matched up with color and letter except the black wire went to E and the blue went to X. My new thermostat has C, L, W2, E, R, G, O/B, Y. So does the blue go to C for my common? Also the new thermostat has a small nonelectric heat jumper (W904) that is supposed to be cut if the emergency or auxiliary system energizes the blower. Or not cut if the system requires the thermostat energize the fan circuit? How do I know if I need to cut it or not?

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