I'm posting this to offer a sincere public thank you to Ken Lenger (Klenger) for the helpful information contained in his website regarding installation of a handy and inexpensive digital thermostat to control RV heating furnaces and air conditioners. The digital thermostat is an easy installation and works very well.
I purchased and installed the $20 Hunter digital thermostat suggested in Klenger's website a week ago when I was in Indiana with temperatures in the 90s and humidity near 100%. The ten or eleven year old OEM Coleman analog thermostat in my trailer had recently failed. It kept the compressor running continuously as the temperature in the trailer declined toward, I guess, the freezing point. I had already made a cursory inquiry of prices for an OEM replacement unit and was quoted a price of approximately $70 plus tax and shipping. I didn't really want one anyway and then I remembered the discussion here about converting to a digital thermostat.
I visited my local Wal-Mart and purchased the recommended thermostat for under $20 and printed out the instructions contained in the website. The only problem I ran into was the website instructions either contained a minor error or were unclear regarding connecting of ground wires. The instructions that came with the Hunter thermostat tell the installer NOT to attach ground wires to the thermostat because doing so would route 12vdc current through the thermostat. The thermostat uses two 24vdc batteries and does not need trailer 12vdc power. Connecting the ground wires to the thermostat might damage the thermostat or the batteries.
However, what I learned was that the trailer's ground wire that was originally connected to the OEM thermostat and the blue (ground) wire coming down from the Coleman AC unit must be connected to each other in order for the air conditioner unit to work. My AC unit would not run until I connected trailer ground and the AC ground wire together. I simply connected them with a butt connector (NOTE:I did not connect either wire to the digital thermostat) and shoved them back into the wall space behind the thermostat.
The new digital thermostat works very well. It displays room temperature as well as the set point for the AC or furnace. I did not perform a scientific test but by simply observation of displayed temperature when the AC unit started and when it shut off in my unit the trailer's inside temperature only ranged 2 degrees from start cooling to stop cooling.
A great improvement for $20 and one hour of work. I recommend the modification to anyone. Even better, the new digital thermostat cost only a fraction of what a replacement old-fashioned analog unit would have cost.
Harvey
I purchased and installed the $20 Hunter digital thermostat suggested in Klenger's website a week ago when I was in Indiana with temperatures in the 90s and humidity near 100%. The ten or eleven year old OEM Coleman analog thermostat in my trailer had recently failed. It kept the compressor running continuously as the temperature in the trailer declined toward, I guess, the freezing point. I had already made a cursory inquiry of prices for an OEM replacement unit and was quoted a price of approximately $70 plus tax and shipping. I didn't really want one anyway and then I remembered the discussion here about converting to a digital thermostat.
I visited my local Wal-Mart and purchased the recommended thermostat for under $20 and printed out the instructions contained in the website. The only problem I ran into was the website instructions either contained a minor error or were unclear regarding connecting of ground wires. The instructions that came with the Hunter thermostat tell the installer NOT to attach ground wires to the thermostat because doing so would route 12vdc current through the thermostat. The thermostat uses two 24vdc batteries and does not need trailer 12vdc power. Connecting the ground wires to the thermostat might damage the thermostat or the batteries.
However, what I learned was that the trailer's ground wire that was originally connected to the OEM thermostat and the blue (ground) wire coming down from the Coleman AC unit must be connected to each other in order for the air conditioner unit to work. My AC unit would not run until I connected trailer ground and the AC ground wire together. I simply connected them with a butt connector (NOTE:I did not connect either wire to the digital thermostat) and shoved them back into the wall space behind the thermostat.
The new digital thermostat works very well. It displays room temperature as well as the set point for the AC or furnace. I did not perform a scientific test but by simply observation of displayed temperature when the AC unit started and when it shut off in my unit the trailer's inside temperature only ranged 2 degrees from start cooling to stop cooling.
A great improvement for $20 and one hour of work. I recommend the modification to anyone. Even better, the new digital thermostat cost only a fraction of what a replacement old-fashioned analog unit would have cost.
Harvey