I'm planning to replace my old mechanical White-Rodgers thermostat (model
1C30-302) with a Honeywell Chronotherm IV.
My house has gas heat only, and uses a 24-volt 2-wire system (white and red
wire). This should be an easy DIY job, but I found the labeling on the old
The old sub-base has 2 connections: one is labeled "4" (connected to the red
wire), and the other is labeled "R5" (connected to the white wire).
I know I need to connect these to the "R" and "W" terminals on the new
thermostat. Unfortunately, the terminal cross-reference for the new stat
don't mention an R5 terminal. So, I don't know which wire should go to
which terminal on the Honeywell.
I suspect since it's just a 2-wire system, it doesn't really matter which
wire goes to which terminal (as long as I connect to the R and W). My guess
is that the thermostat just makes/breaks the connection between R and W when
the stat calls for heat.
Should I just hook the Red wire to R, and the white wire to W?