I am replacing an aprilaire 8444 with a Honeywell RTH20B. The Aprilaire had a small blue jumper wire from A to Ab. The Red wire went into red and the jumper was also in red and jumped to Rb.
The Honeywell has slots for A and Ab but the slots will only take one wire. Do I need to add a jumper to Ab? If so, how do I do it? Can I use a two wire pig tail from the red into the Ab? Please advise.
I meant R and Rc
You just connect one wire to the R terminal and slide the jumper up as shown in the attached diagram.