I’m replacing an old Honeywell T451A. When taking off the old thermostat, there is a metal utility box underneath with 2 wires. One wire says common and the other is heat only. Can you recommend a vertical thermostat to cover this old box? Also what these wires correspond to on a new thermostat? Thanks in advance.
in progress 0Heater-Systems 2 years 1 Answer 393 views