At the risk of sounding crazy, let me tell you what’s going on.
12/27, new Rudd HVAC/heat pump unit & Honeywell TH4000 professionally installed taking advantage of tax credit. 12/29, thermostat suddenly starts showing temp as being 7 degrees warmer than room actually is. Confirmed with other thermometers. Same day, solenoid in thermostat that tells unit to kick on... no longer clicks...unit won't come on. Installer comes out, doesn't have another TH4000 with him, changes face plate only, puts TH3000 face on. Unit fires right up. Beginning Jan 3rd, a few days after that install, my second thermostat started showing that the temperature in the room is 6 to 7 degrees hotter than it actually is in the room. This is the same thing the other one started doing before it stopped working completely on the day it was replaced. To be clear, two other digital THERMOMETERS right by the thermostat have confirmed this temperature variance...in addition to a digital laser thermometer. To be clear…..you can point the laser thermometer directly at the middle of the plastic thermostat housing and it shows the same temp that is on the THERMOSTAT...yet one inch away from the THERMOSTAT as well as the rest of the entire room is showing a temp of six or seven degrees less. There are no light sources, no heat sources or vent near the thermostat. In other words, the thermostat itself is the only thing in the room that IS actually the temperature indicated. To be clearer, the thermostat appears to be generating a slight amount of heat from inside it. Possibly a heat sink within the thermostat or something? The HVAC is working fine but the thermostat has to be turned up six or seven degrees hotter than you want it to be in the room for it to work properly. I’ve emailed the Honeywell folks describing this problem but haven’t received a response. I’ve also been looking on the internet but haven’t come up with anything. I know that we are using the same base plate for both of these thermostats…I don’t know if it could be a problem. In addition, there do not appear to be loose wires connected to the thermostat base. Thanks!