I have a Honeywell T-841A 1316 2-stage, non-programmable t-stat that went bad. I bought a Carrier branded T-841A 1547 t-stat thinking that it was the same thing I had but only with the Carrier name on it. That was not the case. My first T-stat has 9 terminals and 1 hole : X, L, W2, R, G,O, Y1, W1, E, B = blue, not used, white, red, green, black, yellow with metal jumper to W1, white wire from W2 terminal to E. B is not used.
The new "Carrier" labeled unit has 7 terminals and 3 holes without terminals: C, W2, R, E, G, O, Y. If someone has a crossover diagram, if a crossover is possible that would be great. If not, I will get another universal. Maybe this is what I get for choosing the $10 one that says Carrier rather than the Honeywell one for $39.