I needed to replace fan and limit control (White-Rodgers, model 5D51-35), because the fan switch was broken (fan would constantly run) and heat would not stay on.
I took a picture of the control, the way it was wired and labeled the wires. The control had:
- two wires running to the limit side
- one wire running to the lower fan side.
- a jumper copper wire running from the upper limit side to the upper fan side.
When I took the part into the supply store the sales person told me the jumper wire was not supposed to be connected. I installed the new control without the jumper and the heat will come on, but the fan will not come on. The instructions indicate if you have a low volt or millivolt do not use jumper. How do you know if it is a low volt or millivolt system. (I'm using a 120v system.)
Do I install the jumper line because the fan will not come on. (jumper line was connected on old control)