Based on the manufacture's recommendation, I am replacing an old White-Rodgers manual 1F58-77 thermostate with a new White-Rodgers electronic digtal 1F89-211 unit. I have three questions.

1. My current unit is wired to the following terminals: G Y R W2 O E X1
My new unit has the following terminals G Y R W2 O E L C
Question - Which terminal (I assume either L or C? ) do I connect the X1 wire to - and if it is L or C, I assume the other terminal is left empty?

2. In the instructions for the new unit, it states "If your emergency or auxiliary system will energize the blower, then jumper W904 on the termostat must be cut. IF your emergancy or auxillery heat system requires that the thermostat energized the fan circut, do not cut the jumper W904". Question - How do I determine if I should cut the jumper?

3. There is a jumper wire connecting the W2 and E terminals on the new thermostat. In the wiring diagram, it notes "Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency". Question - How do I determine if this jumper needs to be left on the thermostate or removed?

Thanks for your assistance.

Novice123,

Question 1. Go to this link , look up your new tstat and you will find plenty of info. It looks like x1 goes to C from what I see. L is left empty. I believe it is an indicator light terminal. I am not familiar with those units so you are on your own from there.

Question 2. If you have a heat pump with a single control board, the installation instructions for the heat pump will most likely tell you how and what controls the blower. Otherwise you have to be able to read the schematic of your heat pump and figure it out from there. Most likely if the second is the case, the tstat will control the blower. I do not know what equipment you have so you will have to go from here.

Question 3. With MOST heat pumps, yes, leave the jumper in. I have never seen a 2 stage compressor system in a residential situation. The resistance heat unit IS the second stage (W2) of heat. Now if you want maximum $ economy, remove the jumper. You will have to set the switch manually to Emergency Heat whenever the heat pump can't keep up (guesstimate: somewhere below 20F outdoor), but it won't be kicking the electric unit in every time it can't quite keep up. Like when the kids come in from the snow and hold the door open for a couple of minutes. :)

HTH

EPMiller