Digital thermostat

[Donna D.]

Hummm, I could swear (not really) there is some thread here on the EscapeForum that spoke to having the digital thermostat if you have A/C because the wiring would be different.

Am I losing my mind...

 

[gbaglo]

I vaguely recall.
You might search AC with heat strip.

 

[Jim Bennett]

Am I losing my mind...

Yeah, but don't worry, you are in good company.

A simple non-programmable, heating only digital thermostat does the very same thing yours does. I changed mine out, and love it. It is so much easier to read the temperature, and the temperature setting.

You are likely thinking of the folks that want to control both the A/c and heat from the same thermostat. This has to be done at the factory with the wires for the A/C run to the 'stat (as well as those from the furnace), and digital is the only option

 

[Ron in BC]

My thumb hurts every time I turn off the furnace in Ten Forward,

Ditto all the other comments about whether you can retro-fit a digital thermostat.

My primary motivation was the difficulty of moving the on-off lever. I think it was just a matter of time before I broke it.

The secondary benefit is the ease of operation of the digital one. Not just the turning off and on but being able to reach over and easily make temperature adjustments much more accurately than the little lever would allow.

Ron

 

[Rossue2]

Hummm, I could swear (not really) there is some thread here on the EscapeForum that spoke to having the digital thermostat if you have A/C because the wiring would be different.

Am I losing my mind...

Found out that the digital thermostat that controls both AC & heater is only available if you order AC as evidently it is a packaged unit. In other words you can't prewire the Dometic digital thermostat without ordering AC. Weird.

 

[Donna D.]

Yeah, but don't worry, you are in good company.

A simple non-programmable, heating only digital thermostat does the very same thing yours does. I changed mine out, and love it. It is so much easier to read the temperature, and the temperature setting.

You are likely thinking of the folks that want to control both the A/c and heat from the same thermostat. This has to be done at the factory with the wires for the A/C run to the 'stat (as well as those from the furnace), and digital is the only option

So, I was right. Am I going to regret not having the digital thermostat added during the build, even though I don't have A/C, but it's wired for the future?

Flip.. I don't want to run more wire under the "vinyl" when it becomes time to add A/C...

Or, is it okay to change it now (and save my thumb) and everything will be okay when A/C is added (in the future)?

 

[dfandrews]

So, I was right. Am I going to regret not having the digital thermostat added during the build, even though I don't have A/C, but it's wired for the future?

Flip.. I don't want to run more wire under the "vinyl" when it becomes time to add A/C...

Or, is it okay to change it now (and save my thumb) and everything will be okay when A/C is added (in the future)?

Donna,
Am I reading this right: you got the pre-wire for AC? If that's the case, and the extra AC wiring is run to the present thermostat location, then you're close.
The stat that Myron installed is a heating only, on a subbase. The subbase is universal for the mfr's heating only and heating/AC stats. So, when you add AC, you change the stat, but not the subbase, and you have the AC wiring, which just needs to be hooked up.

All ahead, full impulse!

 

[Ron in BC]

Or, is it okay to change it now (and save my thumb) and everything will be okay when A/C is added (in the future)?

No problem at all. The furnace only needs two wires and any thermostat can handle that. Even my basic non-programable one has terminals for A/C that I don't need now. But my trailer (and I believe all are now) is wired for A/C so maybe one day it'll used for that too. Although the power for the A/C is prewired the small thermostat wires for it would still have to be run to the thermostat but with the hollow walls etc. that's not a biggie.

Ron

 

[cpaharley2008]

What the digital thermostat does, with or without the a/c option, is it eliminates temperature swings.
The stock thermostat has a coil spring that heats and cools and this turns the unit on/off. However if set at 68, it will heat until 72, you feel hot. It shuts off and then the temperature starts to drop to maybe 64 before the unit comes on again. this difference in temperature is called the "swing" and the bigger the swing, the more uncomfortable it becomes.
The digital unit can reduce this swing to maybe 2 degrees, on and off temperatures will feel more comfortable. So a digital is my choice.
Now with the a/c, it does the same function, the digital unit will reduce the hot/cold swing that you have with the stock thermostat on the a/c. In addition it will also shut off/on the a/c and eliminate you having to manually turn the unit on/off. Thus the digital option with ETI will make both a/c and heat more comfortable and you will not have to get up to turn the a/c fan off.
It is well worth the $150 option price, IMHO, to control the heat and cooling in your trailer similar to your home set up, assuming you have a modern thermostat at home that is. Myself, I have the Nest- works great
https://store.nest.com/product/thermostat/

 

[Jim Bennett]

So, I was right. Am I going to regret not having the digital thermostat added during the build, even though I don't have A/C, but it's wired for the future?

Flip.. I don't want to run more wire under the "vinyl" when it becomes time to add A/C...

Or, is it okay to change it now (and save my thumb) and everything will be okay when A/C is added (in the future)?

You can swap out the existing one for a simple digital for $30, and 10 minutes work......done. This is what I did.

If you add A/C in the future, you can use the controls on the unit itself, which is quite common. Also something I will have to do if I add A/C, unless one does want to fish control wires in.

You can adjust the anticipator on your mechanical thermostat to cycle to what ever temperature swing you like.
How to Adjust a Mechanical Thermostat

I personally like to keep at least a 2°C (4°F) temperature swing in my trailer to minimize the cycling too much. Each cycle creates the nuisance start-up noises, as well as puts way more drain on the batteries with the fan running a while to ensure the clearing of flue gas before it lights up, on every cyle. I hardly notice the difference snuggled in my cozy bed. Plus, we are fine keeping the overnight temps at 9°C (48°F) at night to help keep the cycling down, and gain further battery energy savings.

 

[Brian B-P]

I personally like to keep at least a 2°C (4°F) temperature swing in my trailer to minimize the cycling too much. Each cycle creates the nuisance start-up noises, as well as puts way more drain on the batteries with the fan running a while to ensure the clearing of flue gas before it lights up, on every cyle.

Good info, Jim.
The purge cycle also blows heat outside, since the combustion air fan is powered by the same motor as the interior air fan - the furnace blows chilled air during the purge. At the end of the heating cycle after the burner shuts off, the interior air is circulated until the heat exchanger temperature drops enough - during that time the combustion air fan is flowing furnace heat outside. I agree - excessively frequent cycling is bad.

 

[MyronL]

It was 44° F or thereabouts in the trailer at 10:45 this morning when I turned the furnace on using my new digital thermostat, set to 55°. Everything kicked on as expected. All windows and doors kept shut.

I keep a separate digital thermometer on the countertop. At 11:25 AM went back into ET-19 to check things out. Thermometer on countertop read a cozy 62° F ...and, around the corner, facing the fridge side of bed the new Digital thermostat said 52° F.

Lesson learned? No surprise. It takes longer for furnace heat to turn a corner and register with the thermostat on the wall. Meanwhile, the rest of the room is cozy warm.

 

[cpaharley2008]

Proper location of the thermostat is critical to comfortable HVAC

 

[Rossue2]

What the digital thermostat does, with or without the a/c option, is it eliminates temperature swings.
The stock thermostat has a coil spring that heats and cools and this turns the unit on/off. However if set at 68, it will heat until 72, you feel hot. It shuts off and then the temperature starts to drop to maybe 64 before the unit comes on again. this difference in temperature is called the "swing" and the bigger the swing, the more uncomfortable it becomes.
The digital unit can reduce this swing to maybe 2 degrees, on and off temperatures will feel more comfortable. So a digital is my choice.
Now with the a/c, it does the same function, the digital unit will reduce the hot/cold swing that you have with the stock thermostat on the a/c. In addition it will also shut off/on the a/c and eliminate you having to manually turn the unit on/off. Thus the digital option with ETI will make both a/c and heat more comfortable and you will not have to get up to turn the a/c fan off.
It is well worth the $150 option price, IMHO, to control the heat and cooling in your trailer similar to your home set up, assuming you have a modern thermostat at home that is. Myself, I have the Nest- works great
https://store.nest.com/product/thermostat/

What is still unclear to me is whether the AC unit you have w/digital thermostat option is the same as one without the digital thermostat option. Does yours have the manual controls on it? Even though I didn't want AC I was willing to pay for the digital thermostat should an AC unit be installed in the future. ETI said that was not possible, hence my belief that it was a coupled unit and needed to be purchased as a set. If not, then wondering why I couldn't have had at least wiring run for a future thermostat upgrade able to control both units.

 

[cpaharley2008]

Yes, the Dometic a/c that comes with the thermostat is different that the Dometic non digital install because the controls for the fan and thermostat is in the ceiling unit. I have no control in the ceiling unit, just on the thermostat. The stock a/c also must be turn on/off manually, the digital set up is controlled by the thermostat on the wall. Similar to having an a/c window unit that needs to be turned on/off versus having central air with a thermostat.

 

[escape artist]

Hi: Rossue... Our A/C unit has its own controls. We have the analogue thermo. If you want a didgi. thermo... you need the A/C unit without its own controlls, coupled with the furnace although there may be some exceptions to this rule. Alf
escape artist N.S. of Lake Erie

 

[Rossue2]

Jim/Alf- that's what I thought and remember back when this topic came up in the past seeing some units without controls. Still, it seems their should be an option to at least pre-wire for that dual-control digital thermostat so one doesn't have to go fishing wire later to do it, yet ETI said no way other than get the AC now.

At least our standard thermostat is much easier to turn on/off than the previous one on our 17B so anyone with that problem can probably get that fixed without much trouble.

 

[vermilye]

Those (and other) settings are only for at least 3-wire setups with a separate fan wire. Our furnaces are all 2-wire, all (heat AND fan) or nothing

Actually, most thermostats, including a 2 wire digital thermostat CAN have a heat anticipator. Some of the older 24V thermostats had a resistor across the 24V line that worked as the anticipator by adding heat to the thermal coil that tilted the mercury vial that acted as the switch.

My new digital thermostat lets you select one of 3 "delay" settings (they don't even call it an anticipator, but that is what it is) that determines how far over the set temperature the contacts will stay closed. You may have to dig into the "manual" or go on line to find out how to set it, but if the furnace cycles too often or not often enough, changing the setting can be helpful...

 

[FMLNM]

Only thing to worry about is making certain the thermostat you buy is millivolt compatible, meaning it likes 12 volts.

....which the one I installed and the slightly different model Myron installed are.

 

[MyronL]

With all due respect, I got now to expel some thermostatic liquids and solids:

This issue before us, of needing to control both the heat, and the cold, with a single central control point, i.e., the thermostat, seems farcical to me on its face. In Siberia, when it is cold enough outside you got your furnace -- you turn it on; you warm. In the South of Texas, or the FLA-Keys, where ever, man, it is so tropical, so hot outside you got to get relief, you turn your a/c on, you cool.

I have great trouble believing either extreme is ever happening anywhere in the same place on the same day. Hence, is not each unit better served with its own controls?