am replacing a faulty #56 on a model 400 humidifier. The wiring on the 56 only had 3 connections (2 wires for each one): 24V AC, A/A and outdoor temp sensor. The connections going to 24V AC are going to a separate junction box mounted on the side of my furnace. How do I know if this is a constant supply of 24V power and this should be the connection going to R and C on the new #58? Also, the "A/A" connection on the old 56 go to the humidifier itself - is this the connection that goes to the W/G and Cf on the new #58?
Use a meter to see if those wires have 24 volts all the time or not.
The HH terminals go to the humidifier.
CF wires to the common on the furnace control board.
W/G wires to W of furnace control board if you want it to only operate during a heat call.
or you can wire it to G if you want it to humidify anytime the fan is on.
this doesnt add much to your question, but you will love your 58, I put one in last month and it's automatic switching controls are awesome when used in conjunction with the outdoor temp sensor.. no more guessing the humidity, just set it and forget its there!