Ok everybody...I'm pretty new and I know this has been covered quite a bit, but I just wanted to throw this out there.I have a 2014 StarCraft AR-ONE 16 BH. We did some colder weather camping this spring and the furnace ran fine. However, as many mention, the "hysteresis," or furnace operation occurs with giant swings. The problem is that our TT is quite small and it will get fairly cold (several degrees below the set temp) then kick on like a blast furnace and get many degrees above set point before turning off. My wife pretty much refuses to camp when the furnace is required because she gets so uncomfortable with the super high heat blasts.I took the TT to a local place here in PHX called RV master techs and asked if they could install a digital thermostat. They said, yeah, should be no prob. About a week later they acted hesitant to do it and that "it wouldn't make much of a difference because your TT is so small...you just need to deal with it."I'd read all the threads on installing a battery operated digital thermostat (the Hunter model from Wal-Mart) and mentioned it...he seemed to blow that off.So, I want to install the hunter thermostat myself. However, I'm a little worried about the wiring. I have an atwood mechanical thermostat now and the basic small atwood furnace. My AC is a totally separate system and doesn't use a thermostat.Has anyone wired the Hunter thermostat for furnace alone, and how will I know which wire goes where once I open it up? Also, if the thermostat uses batteries, does it still have to be connected to the DC power wire (I'm assuming there is one in there). Anyway, I'm sure it isn't hard to do, but just looking for someone who has done the same and specifically with an atwood furnace/thermostat.

The Hunter will be an improvement but it will still allow the heat to over shoot the set point. In my case this was by 3 degrees.This is because when the room hits the ratget temp, the stat turns off the furnace. Unfortunately the furnace has to run another 60~90 seconds in order to cool down it's heat exchanger in a manner that keeps it from cracking. This is what makes the furnace over shoot the set point. The smaller the area the worse the effect.If you get an Energy star rated stat (like I finally did) it will take this over-shoot issue into account and will shut the heat off just before the set point. This allows the cool down period to heat the room to its exact set point.The ES rated stat will keep the heat and AC much tighter and use less energy too.

Heat only should be a slam dunk. Hunter will explain heat only connection.Or consider a heat only thermostat. HoneywellAlso consider a radiator style electric heater to even out the heat some and reduce furnace run time.I would be inclined to get an Atwood digital replacement although it will probably cost more.

Do you guys know if you have a basic mechanical thermostat like Atwood, are there just 2 or 3 wires? I have mine in storage now and can't access it.

smkettner wrote:Heat only should be a slam dunk. Hunter will explain heat only connection.Or consider a heat only thermostat. HoneywellAlso consider a radiator style electric heater to even out the heat some and reduce furnace run time.I would be inclined to get an Atwood digital replacement although it will probably cost more.Yeah I looked at the one they offer and it looks like it is built to do many more functions. My furnace is the most basic possible

No matter the circumstances, I would think you will be happier anyway. I installed a new digital thermostat last Spring. Could not be happier !!!!Basic furnace operation in my TT / 2-wires.The install was super simple, took about 5-minutes.Honeywell # RTH5100B

Another digital thermostat question | Good Sam Community

19 Replies

JLTN_James
Explorer
Nov 04, 2014
Nice explination Old Biscuit!

I think the OP will be much happier & more comfortable with the digital programmable model. I made the swap two seasons ago in my pop-up. It made a big difference keeping the temperature steady. Plus I don't have to get out of bed to turn the heat up in the morning!
Old-Biscuit
Explorer III
Oct 28, 2014
scout266 wrote:
Yeah that makes sense I'm just trying to figure out why one of the wires going into the thermostat comes from the 12 V DC batt.

Because that 12V DC is used to trigger furnace fan.

1.The Thermostat calls for heat, sending DC current to the furnace.
2.A Time Delay Relay is energized and passes battery DC power to the blower motor. (can be a stand alone component OR timer on circuit board)
3.The blower motor and fans spin, pulling air from the Air Return and generating a stream of air through the Heat Exchanger and out the Ducts. At the same time another fan pulls air from the Combustion Air Intake into the Combustion Chamber and out the Exhaust.
4.The fan air stream causes the Sail switch to close as the blower gets near full speed.
5.Power flows to the High Limit Switch and onward to the Control Circuit Board.
6.The Control Circuit Board opens the gas valve and generates a spark at the DSI Igniter.
7.The Burner ignites, building heat in the Combustion Chamber.
8.Heat passes through the Heat Exchanger, warming the air circulating through the Ducts.
9.The Thermostat reaches the Set Temperature and opens.
10.Power is removed from the Control Board and the Burner shuts down.
11.The fan continues to run to cool the furnace, until the Time Delay Relay opens again. (or timer on circuit board times out)
YamaDooed
Explorer
Oct 28, 2014
It functioned fine as in no more 6 degree temp swings but the switches located on the bottom are a PIA for my non dainty fingertips to operate. I used it till my WR thermo arrived which was only 2 days.

I also have the toggle switch hi/lo mod which works well for ac units...

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scout266
Explorer
Oct 28, 2014
Yeah I saw this one online but couldn't get it before my next trip. How did the honeywell one work for you?
YamaDooed
Explorer
Oct 28, 2014
I installed the same thermostat and removed it after I found the one I wanted.
They also sell heat only models for $25.

White Rodgers Thermostat with backlight and current temp and setpoint temp display.

Moderator edit to re-size pictures to forum limit of 640px maximum width.
YamaDooed
Explorer
Oct 28, 2014
The thermostat is just a basic on-off switch on a two wire system.
scout266
Explorer
Oct 28, 2014
Yeah that makes sense I'm just trying to figure out why one of the wires going into the thermostat comes from the 12 V DC batt.
time2roll
Nomad
Oct 28, 2014
The thermostat is just a battery operated thermostatic switch.
You could put a toggle switch on those wires and cycle the thermostat manually.
Or just twist them together for on, separate for off.
scout266
Explorer
Oct 28, 2014
Maybe a dumb question, but if this is battery powered (AAA batts) why would I have to have a wire from the 12V DC TT battery connecting to the thermostat? Is it just for completing the circuit, etc?
scout266
Explorer
Oct 28, 2014
Hey everyone, thanks for the help. Can't wait to get out there and try it. I am actually somewhat mechanically capable (fly jets for the Air Force) but when it comes to wiring/electricity I am an absolute idiot. I was stationed overseas and had to hang all my own ceiling lights and got a nice 220V shock a couple of times.