Hiya I hope someone can help. I'm trying to replace a Honeywell ST7100 with a Centaurplus C27. The only problem is that on the instructions it says to replace N-N, L-L, 1-7, 2-4, 3-8 and 4-5 but the Honeywell only has wires in 8, 6 and 3??? It has wires in the CH and HW on and also a terminal called Com. I don't understand, please help