Programmable thermostat

[davidsimmonds]

Does anyone know of any programmable thermostats that would be usable on a 5th wheel system? I know that household units won't work since I think they use 24-volt circuits.

 

[Gary RV_Wizard]

Don't know of any but hope you find one. I'd like to install one too.

 

[John From Detroit]

Though they may be designed to control a 24vac system,,,, Odds are many designes will work on 12vdc if connected properly.  You need to contact a manafacturer or three to make sure however.  I can not make any suggestions as o brand.  Visit a store which sells them (Home Depot? Lowes? Mennards?, whatever) write down some brands and web sites and visit.

 

[davidsimmonds]

I looked at the inside of my 5er and I see a wired labelled 7.5V. I figure that means that it needs a 7.5V feed. If a programmable unit requires a 12V or 24V feed, that might disable the whole idea.

 

[davidsimmonds]

I recevied this back from a rep from White-Rodgers:

"Depending on your connection requirements, consider the 1F78-151. Link below to the specifications. Ratings on the cataloig page are millivolt to 30 volts AC or DC.
http://www.white-rodgers.com/wrdhom/common/ptech/thermo/info_list_ss.htm
#1F78-151"

It might be worth a try.

 

[Gary RV_Wizard]

I was looking at Programmable t-stats in Walmart the other day and most of them are rated 24V and compatible with "millivolt systems".  If millivolt implies it works with very low voltages, any of them should do the job.  Millivolt models from Honeywell and Hunter were on display.

 

[davidsimmonds]

According to the people that I spoke with, there is 24V systems and not-24V systems. The not-24V systems are considered milli-volt (bizarre naming though)

 

[Gary RV_Wizard]

Dunno, but the models I saw claimed compatibility with both.

 

[davidsimmonds]

I guess the best thing is for me to buy one and try it out. Most places I have seen them have a good return policy.

 

[Bob Buchanan]

Does anyone know of any programmable thermostats that would be usable on a 5th wheel system? I know that household units won't work since I think they use 24-volt circuits.

Here's a fellow that modified a home programmable for an RV:

http://home.comcast.net/~morodat/ritetemp_install.html

 

[Jeff]

I'm not sure we are talking about furnaces or air conditioners and I do not know about other units Ac's but our Dometic air conditioners have three speed fans that automatically drop from high to medium and low as the spread from current temp and the temp called for on the thermostat is above or below certain values, for instance I remember it drops to low fan when the delta is less than 4 degrees.

I doubt that these off-the-shelf units will be able  to accomplish that.

 

[davidsimmonds]

My manual thermostat unit has a hi-Fan and a Fan connection, but I don't know if that is for the A/C or not. I have the following connections:

+7.5V
Cool
Heat
Hi Fan
Fan
Ground

 

[davidsimmonds]

I spoke with a technical rep with Coleman RV Products. He said that household programmable thermostats will not work in an RV. The main reason is that the thermostats in an RV feed power to the control panel of the furnace and the airconditioner. This functionality is not available to the household units. He said that of the three major RV thermostat companies, none of them supply or build a programmable unit. It must have to do with the number of sales they would get compared to the manual systems.

Oh, well, it was worth a try.

 

[Karl]

Jeff,

I agree. On many rv heating/cooling systems, there are no individual thermostats, but merely a thermistor which changes resistance with temperature, and that feeds the main control board. The anticipator(s) are on the control board, as is the high/medium/low fan  selection circuitry. While it may be possible to interface a home-type automatic thermostat with it, it would be quite difficult. Also, if you have two furnaces or air conditioners, the problem gets much worse - you may have two thermostats fighting each other; one trying to cool as the other tries to heat

If you're a 9 to 5'er, you may see some energy savings, but having had one myself (in my home), I would often kick it up or down a few degrees depending on how hot or cool I felt. Automatic as they are, they still don't take into account the humidity, which has a great bearing on your feeling comfortable or not; regardless of temperature.

 

[Gary RV_Wizard]

Basement air systems appear to use residential-type a/c units. It might be practical to use a residential t-stat with them.

 

[Bob Buchanan]

Jeff,

I agree. On many rv heating/cooling systems, there are no individual thermostats, but merely a thermistor which changes resistance with temperature, and that feeds the main control board. The anticipator(s) are on the control board, as is the high/medium/low fan? selection circuitry. While it may be possible to interface a home-type automatic thermostat with it, it would be quite difficult. Also, if you have two furnaces or air conditioners, the problem gets much worse - you may have two thermostats fighting each other; one trying to cool as the other tries to heat

If you're a 9 to 5'er, you may see some energy savings, but having had one myself (in my home), I would often kick it up or down a few degrees depending on how hot or cool I felt. Automatic as they are, they still don't take into account the humidity, which has a great bearing on your feeling comfortable or not; regardless of temperature.

Did you review the link from my post below, Karl? That fellow seems to have the exact kinda A/C and Furnace that I have had in my last 4 RV's -- with a high and low fan speed. Obviously his works.  ??? ??? Can't imagine he would go to the trouble of posting if it didn't.  If it does work, someone like you could mass produce them and make a fortune.

Actually, the only reason I would need one (and it's a "biggy" to me) is so on really cold AMs such as one gets in Reno in mid winter -- I don't have to get out of bed to turn up the heat.    Or does your cat do that for you . . .

 

[davidsimmonds]

I'm not trying to save energy. We're not full-timers either. Long way from retirement (well, not too long, maybe 15 years). We've just gotten used to the programmable units that I have in my house. I just need to get used to turning down the A/C and the heat at bedtime and putting them back on during the day if necessary. It would be nice to wake up to a nice warm unit at some locales.

 

[Karl]

Bob,

Yes, I did read the article, and saw that he installed a MANUAL fan switch.

 

[Bob Buchanan]

Bob,

Yes, I did read the article, and saw that he installed a MANUAL fan switch.

Karl,

From his article:

Quote: At Home Depot I found a nice programmable unit called the RiteTemp 8022 that was only $12.95 after an energy-saver rebate from the electric utility.UnQuote.

Why would one "program" a manual switch?? ???

From the user manual, I see a lot of programming available for a MANUAL switch.?

http://www.ritetemp-thermostats.com/images/8022_operation_guide.pdf

Or did he buy a programmable unit just for the digital readout?

 

[Karl]

Bob,

Or did he buy a programmable unit just for the digital readout?

Could be. The Dometic (DuoTherm) Control Centers have a digital readout, but the regular thermostats do not. They do have a 2-speed fan switch, however, so the wiring was probably already in the wall for it.