I'm trying to install an Aprilair 700m on a carrier weathermaker infinity 58MVP furnace. Do I have to use supplied transformer? Can I connect to Hum and C on circuit board without using transformer? OK to plug into outlet that only has power when fan goes on?
press the door switch in and keep it closed with tape. then start the furnace on heat and after the fan starts see if you get 24 volts AC from Hum to C. If so then you don't need the transformer. plug the unit into a wall plug, only needs power when the fan is running but a wall socket is OK.
"Cut it twice and it is still too short".