I wish to replace my Carrier humidifier with an Aprilaire 700. I have 3 questions related to properly connecting my Carrier Infinity 96 furnace's HUM terminal to Aprilaire 700 (24 VAC line):
1) I see only one HUM terminal on my Carrier Infinity 96 furnace circuit-board. I remember seeing a response to a question on "Home Improvement" that said that there should be 2 HUM terminals. Given my situation (one HUM), where should the other line to complete the circuit from the transformer be connected to complete the circuit? Should I connect it to the black/common terminal?
2) One comment in "Home Improvement" said "When the furnace is running in heat mode, you should measure ~120 volts...." So, does it mean that the HUM terminal drops to near zero volts when the heat is off? i.e. does HUM line function as a relay-switch or should I insert a relay between my Carrier furnace and Aprilaire humidifier?
3) What is the VAC on the black/common terminal in Carrier Infinity 96? If I connect the HUM terminal (120 Volts) to the black/common terminal (24 VAC as I read somewhere on the internet), would it burn my circuit board since the black/common line is really not a grounded line but one carrying 24 VAC.
Could someone help me please so that I don't mess up?