Hi, I am trying to replace an old manual thermostat with a Honeywell RTH221 digital. The problem is I have 3 wires Red, Black, and White. When I touch the Black and White in anyway the heater turns on. I have no idea what the Red wire does seeing as it was not even hooked up to the old thermostat. If anyone has any suggestions that would be great. Thanks

Here is an old thread talking about a situation like yours. https://www.askmehelpdesk.com/heatin...at-152679.html Are you following the installation manual? How to Install a Programmable Thermostat (Example: Honeywell) on One Project Closer