Lazy Daze Owners' Group

Just to present alternatives. Dave K. and I both got this one.  Emerson 1E78-140 Non-Programmable Heat Only Thermostat for Single-Stage Systems
   It is narrow, I wanted to preserve space on the wall next to the dinette. It is labeled White Rodgers on the picture, but is made by Emerson. It uses three AA batteries. The comment about 24 v. means it will work in up to 24 volt systems. For the motorhome it works fine on the 13 volts.  Just two wire connection, red and white. The polarity doesn't matter.  I haven't replaced the batteries yet, over two years operation so far. The yellow back light comes on when a button is pushed for a few seconds. Easily visible in daylight also. (edit) enabling the back light does take a few button pushes, it is optional. Read the reviews or the included instructions. maybe a little tricky, but just need to do it once. (and maybe when changing batteries.)
   I like this one because it can be turned on and off with the slide switch at the bottom. When off it displays the temperature.  When on, it displays a little flame icon, and the set point temperature (smaller) next to the temperature display on the left. It cycles on and off in one degree, with a settling time to prevent nuisance quick cycling.  About $30 at the moment.   I guess it can be painted if desired. Mine is mounted on a white wall.  RonB

Looking through the reviews on that Emerson thermostat; one had a picture of corroded traces on a pcboard (pcb).
    It looks like it was placed outdoors, or in a very humid area. That corrosion is not typical. I don't think mine will act like that. A review by Richard Iwanski, (5 star) had a good picture of the backlight, and instruction on how to enable it to come on. The RV furnace is not a milivolt system. Such systems require a standing pilot to generate electricity from a thermocouple. This current and millivoltage is switched by the thermostat to turn the gas valve on and off, and the pilot light ignites the gas. In an RV heater the 12volt supply,(main house battery)  that also runs the fan and logic, does the 'heavy lifting' and the thermostat just instructs the heater unit when to turn on and off.  Many of the negative reviews seemed to be from people who had never worked on any of this type of circuitry. They understandably were further frustrated by poorly written instructions that seem to be the 'norm' anymore.
     In addition, a button press doesn't do anything but turn on the backlight. A second button press while the backlight is on does the expected operation. Even in daylight, hard to see the backlight, this holds true. If you don't hit another button during the 3-4 second window, it will give the appearance that it is ignoring your button presses.  This actually is a pretty common software method. Maybe why it is so 'tricky' to turn on the back light function.
    For the non white thermostat housing people, here is one about the right price.  ELECTECK Digital Thermostat with Large LCD Display, Non-Programmable,...
  It doesn't cool, and can't just run the fan only. But otherwise should work.     RonB

Is it just couple of screws and joining wires?