Programmable Thermostat

[John Mo]

I have a Sightseer with two thermostats. One controls only the rear air and the other controls the front air and furnace. I'd like to swap out the front thermostat to better manage the furnace in the winter. Does anybody know if that's a simple 1 for 1 swap?

[TXiceman]

Not that I know of. You are pretty much stuck with the sorry t'stat provided on the unit unless you want to do a lot of rewiring.

Ken

[Muddypaws]

If your t-stat is anything like mine it uses remote sensors. I don't recall seeing many programmable ones with remote sensor inputs. But I haven't looked very hard. And if such a thermostat were available would it work with the existing sensors?

BUT: There is a way to do it, but it's probably more expensive than it's worth. > $250

I installed a wireless system in my house that uses two portable sensors. It is a Totaline P474-1100RF, but there are plenty of others on the market now.

The 'gotcha' is that most home systems requires 24VAC. But I'm sure there are 12V DC systems out there, probably some that run on their own batteries, which would be a good choice if you boondock often.

[John Mo]

I'm pretty sure I don't have remote sensors. That's been one of my beefs with the HVAC in the Sightseer 35J: both of the thermostats are only a few feet apart and in the back third of the unit. The bunk room gets really cool and I cook up front.

It looks like something like this Dometic thermostat would be a nice improvement for both the AC and the furnace as it would add remote, wireless sensors. I'm not sure it would be a compatible replacement for the Coleman thermostat and roof units.

[John Mo]

For posterity, here are the answers:

None of the Dometic thermostats will work with the RV Products Coleman A/C units. Dometic, Winnebago, and RV Products all told me the same thing.

RV Products makes a thermostat that has remote sensors, but they don't offer anything that's programmable. They said they've looked into it and it would be a $400 thermostat. RV Products said getting such a thing to work on 12 volts is a big deal. That kind of left me scratching my head as many thermostats run on AA batteries, but maybe it has more to do with the 12-volt control circuits of the A/C and furnaces rather than the logic board and clock in the thermostat itself.

In any case, you can't get there from here.

[Muddypaws]

I replaced the POS thermostat in my previous RV with a household thermostat and it worked fine. Better than what I took out. But along the way I had to re-wire the air conditioner with a kit to make it compatible with household thermostats. I forgot about that. I'm glad someone caught it before you did anything.

If you talk to the manufacturer of your A/C unit(s) they will probably know what you need to do.

There are programmable ones that have their own batteries so 12/24 voltage shouldn't be a problem. The switching voltage shouldn't matter.

I like the looks of the Dometic, but I don't trust Dometic. The POS I took out was made by, you guessed it, Dometic. but if anyone sells them on Amazon.com you can probably find trustworthy reviews.

[Dunner]

Don't know if this will help, but I put two Hunter stats in my MH.

http://www.irv2.com/forums/f101/furn...at-122160.html

Hunter Thermostat

[John Mo]

Originally Posted by Dunner

Don't know if this will help, but I put two Hunter stats in my MH.

Hunter Thermostat

Huh. Well, this makes it look like you could use any old household thermostat and I don't know why you couldn't use a programmable one. Unfortunately, the programmable ones are a little too pricey to experiment with.

Is there something special about the Hunter model referenced in these mod articles?

[bluepill]

John Mo: If the only function that you want is a night set-back for the heater, there is an old DIY trick that requires no new thermostat. Put a small wattage lamp (like a night light) a few inches below the thermostat, and connect it to a cheap plug-in timer. The heat from the lamp fools the thermostat into thinking that it is hotter than it really is, and in effect sets back the temp.

[Dunner]

The Hunter t-stats are only $20 at Walmart. I think the programmable ones are $30.

[John Mo]

Originally Posted by bluepill

John Mo: If the only function that you want is a night set-back for the heater, there is an old DIY trick that requires no new thermostat.

I appreciate the low-tech approach, but I'm looking for something to dial the heat back through the day and all weekend. I am going to take my Winnie to a job out of town. I'd like to warm it up around breakfast and supper 4 days a week and let it sit at a minimum level most of the time.

[drfife]

Originally Posted by Dunner

Don't know if this will help, but I put two Hunter stats in my MH.

http://www.irv2.com/forums/f101/furn...at-122160.html

Hunter Thermostat

I installed a digital Hunter thermostat in a travel trailer I once owned.

[Dunner]

I believe the color coding of T-state wires is universal. Just leave the red power wire off if it uses batteries. I'm going to look into using an LM7803 regulator so I can use the 12 volts and eliminate the batteries. I have this fear of batteries leaking, destroying the devices they are in. I will not use Eveready batteries. They are programmed to leak.

[rwhit]

I installed a Hunter stat in my minnie works great keeps it right at a set temp. the only thing different is you won,t use the red 12 volt power source. The stat is battery operated. Just remember to change the batteries, and keep some handy you'll lose your heat/cool with out them.

[Dunner]

I'm currently working on a LM317T adjustable regulator circuit so I can use the "red" 12 volt wire. RadioShack has the 317 for $3. They don't have a LM7803 or I would use it. The rest of the parts came from my spare electronic parts bins. if it works.

LM317 Voltage Regulator

[Dunner]

It works off of my 12V computer power supply.

[Muddypaws]

Originally Posted by Dunner

I believe the color coding of T-state wires is universal. Just leave the red power wire off if it uses batteries. I'm going to look into using an LM7803 regulator so I can use the 12 volts and eliminate the batteries. I have this fear of batteries leaking, destroying the devices they are in. I will not use Eveready batteries. They are programmed to leak.

Wouldn't you lose your program when the 12v supply is turned off? Maybe a pair of rechargable batteries that get charged by the LM7803 when power is on would be a good compromise.

[Dunner]

I don't program it. Just set it till I'm warm. The circuit board I made fits where one of the batteries would be.