Stupid Thermostat. How to get a consistent temp while winter living?

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mrlegoman

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Oct 23, 2018
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9
2018 Coachmen Chaparral 5th wheel - Virginia

We are having a really hard time trying to figure out what should be a simple thing. Two zones, living area and bedroom.  First night it dipped below 60, we set the state to 'elec heat' at 67 degrees. We wake up to the bedroom at 80. Even though it was set to elec, the gas was kicking on in the living area. The floor ducks for the gas heat branch to both. So the living area was 65 trying to heat up to 67. While the bedroom was cooking at 80+ (we had the door closed).  Still no clue as to why the gas heat was on at all.

Second night it dipped below 50 out. Again we set stat to 67, elec heat and leave the bedroom door open.  No gas heat this time. But overhead units run all night and inside temp doesn't get above 60. So we're at that weird temp where the comforter on the bed roast us, but without it we freeze.  No gas heat kicking on at all this time (even though we had not changed anything) But according to the thermostat manual, if there is a 5 degree delta, gas will auto kick on. But it never did.....

Third night. Ok tired of being cold, turned stat to Gas Heat and 67. Both rooms heat up to over 70 and gas heat is still blowing out. Had to turn the stat to 'off' to shut air off. Geeze.

Last night. Set Gas Heat to 65. Got a small ceramic heater for the bedroom and set it to a mid level. Set the elec 'fireplace' on low and an 8hr run time. Actually got some sleep. Main room was still about 62 when we got up.

Is this typical for these units? I've read on other post that we shouldn't need gas heat until we get into the 30's.  But our overheat units seem to barely work in the 50's.
 
S

sightseers

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RV's are notoriously bad in both cold and hot weather....about the only solution is to move them to a better climate.

Be thankful they put wheels on 'em  :) 
 

Old_Crow

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Nov 20, 2016
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Tom's Place, California
Are your a/c units heat pumps, or are they regular a/c's with optional heat strips? 
If it's just the heat strips, they don't put out real hot air,  just enough warmth to take the chill off in the morning.
I know on our coach with dual zone ducted roof air and regular propane only heat, I have to set the salon temp around 10* higher(or lower as the case may be)than the stateroom temp to keep the whole coach the same temp throughout.
 

mrlegoman

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Oct 23, 2018
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Old_Crow said:
Are your a/c units heat pumps, or are they regular a/c's with optional heat strips? 
Good point, I'm going to have to look into that because I'm not sure.
 

Scott 3

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Jan 17, 2016
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Your ceramic heater should do a better job considering the external temps you mentioned.  You might need a better ceramic heater if it cannot keep your bedroom comfortable.
 

Gary RV_Wizard

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West Palm Beach, FL
You almost surely have heat pumps since there is an electric heat option on the t-stat.  The zone controller has logic that detects when the heat pump is unable to raise the temperature adequately and calls on the furnace for an assist. Typically this happens if the set temperature is more than 5 degrees above actual, but some of them also trigger on time, i.e. the heat pump is running but the temperature doesn't change much. Or at all.  Surprised, though, that you don't have separate furnaces for each zone, so that only one or the other heats.  Is there only one large furnace rather than two separate furnace heat zones?


Sounds like your heat pumps are NOT working adequately, or maybe not at all. They should produce plenty of heat at any outdoor temperature above 39-40 F.  That would seem to the root problem - the rest is the system trying to compensate for lack of electric heat.  What make & model of heat pump do you have? Not that is should make any difference - both Dometic and Coleman Mach work about the same and should be entirely adequate at those temperatures.
 

John From Detroit

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Apr 12, 2005
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26,278
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Davison Michigan
Describe your thermostats... My RV from factory had Carrier Air V's with IR remote controlls. the T-Stat is located in the air conditioner air intake. Worked good with fan set to HIGH in summer but when it got cold same thing happened to me as to you (only on gas I dont have the elecrict option)

I found a fan about 4 or 5" 12 volt "Clip on" pointed toward the blanged sensor did wonders for regulation.

Now I use space heaters they do much better.
 

glen54737

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Oct 26, 2007
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Chesterfield Mi
You might want to locate the temp sensors. I had the A/c kick on in the middle of winter because the toaster was right under my temp sensor. The ones in my fifth wheel were little white discs with a grid on the front.
 

Old_Crow

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That's funny, Glen.  Before we got our Keurig, we had a regular MrCoffee sitting under our sensor.  I couldn't figure out why it got so cold in the salon in the mornings before the heater kicked in.  Heck, it was set okay in the evenings.
 

RVRAC

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Jun 11, 2012
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Until we got this unit that has two furnaces with two separate thermostat, the two prior units have an area that was warm and another area that was not as warm to cold.  This feature was one of the things we like about our present unit. I still think that the thermostat in RVs are all "optimistic", cannot trust them.
 

Gary RV_Wizard

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Had a 5W with the thermostat mounted at the entry to the hall to the bedroom, with an a/c outlet above. A/c cycled off quickly cause cold air blew directly on it.

Had a coach with the front zone thermostat under the cabinets adjacent to the stove. If cooking anything, the t-stat read several degrees high and the a/c ran non-stop. In the same coach, the rear zone temp sensor was under a cabinet over a bedroom window. The sensor heated or chilled in proportion to the air temperature outside (radiating through the window glass).

In another coach, the tstat was in the hallway from lounge/galley to the bath/bed area. It was the warmest place in the coach - isolated and no windows near by. Front of the coach got cold or hot while the t-stat saw only pleasant temperatures. Sometimes we put a small box fan in the hallway to help circulate interior air so that the thermostat reacted sooner.


Yeah, there are some pretty cheap thermostats in some rigs, but most of the problems are HVAC system design (or lack there-of), not the quality or brand of thermostat.  The biggest problem with the cheaper RV thermostats is that they allow the temperature to  go as much as 2 degrees colder or hotter than the set temp before signalling the a/c or furnace. That exacerbates the uneven temperatures inside any RV and can lead to a lot of discomfort. The better tstat models hold to 1 degree or maybe even 0 degree deviation. That makes the a/c or furnace cycle more often (which some people find irritating), but it holds the temperature to a more narrow range.
 

wackymac

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Dec 9, 2008
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676
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Ocala, FL
No problem with our budget coach.  35k btu propane furnace in a 31' with no slides.  Thermostat is in the middle of the coach.
 

vinceherman

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Dec 31, 2014
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218
Location
Ohio
My Chapparal is slightly order.  No heat pump, just gas.
Every year we camp for a week in the Catskill mountains in September.
Some times in the 80's.  And it snows some times.
We typically have the thermostat set a few degrees lower than is most comfortable, and then augment that with a tiny ceramic heater in each bedroom.  That way, we in ours, and Mother in hers, can adjust the sleeping temps to our liking.
 
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