On a brand new oil furnace the burner works fine but the what seems to be a 2speed blower will not start. The limit switch shuts the furnace down after heat rises. It resets after it cools down. Restarts but still no blower. When I bypass the motor relay the blower will spin fine. Same with the delay switch. I ordered replacements for those switches and will try that. But I Am wondering if the limit switch could be at fault? or is there any other link in the blower circuit that might be causing this? It's a new appliance. The plenum and ductwork are open and free. I checked the wiring diagram and all wires are plugged in where they need be. I'd appreciate your help.