DIYbanter - View Single Post - Programmable Thermostat wiring question -rth7500

wrote:
May I ask why Page 18 of the honeywell manual show that RH, 4, or V =
R, versus what you show as 4=W?

I noticed that too, Dave. All I can conclude is that some thermostat
manufacturer out there must use the 4 terminal to designate the transformer
hot side. By looking at the WR schematic you'll see that on your thermostat
terminal 4 is used to actuate the heat valve (the W terminal).

Wire it up and let us know how it works.