OK, I STILL CANN'T REMOVE THE PLATE INSIDE THE COVER TO GET TO THE MOUNTING SCREWS & WIRES. LET'S SAY I PULL THE THING OFF THE WALL TO GET TO THE WIRES. WHAT ABOUT IDENTIFYING THE WIRES FOR CORRECT PLACEMENT INTO THE NEW THERMOSTAT.
I have a white-rodgers thermostat for a heat pump tht is 13 years old I want to replace. I can not remove the the plate covering the wires. I have removed the outside cover and revealed the mercury ampules but can not get to the screws on the inside to get to the wires. What is the trick?