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Thermostat warm-up


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#71 Wallowa

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Posted 18 January 2016 - 07:54 PM

Good question..  Safe bet is that the appliance has an automatic shut down if propane or electrical power [ igniter ] is not available at the valve.  Like most modern home appliances.

 

Otherwise the liability would be enormous.

 

Not having taken delivery of our Hawk, I have no idea of how the propane bottles are connected, nor disconnected.  I was planning on a bottle gauge but that may not be needed or possible.

 

Devils advocate; if the WR goes to 45 degrees but the Honeywell goes to 35 degrees is that alone sufficient to change thermostats?  If my intent is to prevent freezing of water in lines and fixtures my guess is that 45 degrees might do the trick but that 35 degrees might not.

 

I realize that propane is a limiter for extended camping off the grid; but will the Honeywell save significant propane and battery electrical?

 

Not adverse to changing out a new thermostat and will do so if it makes sense.

 

Thanks for all the input!

 

Phil


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#72 ckent323

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Posted 18 January 2016 - 08:13 PM

Phil,

 

Water must get to and stay at 32 degrees to freeze.  IF the thermostat keeps the temp above 32 degrees (i.e. 35) then the water will not freeze.  The question is what is the temp at the water vs the thermostat.

 

To make an extreme point if the water tank is steel and the tank is sitting on steel (or some other conducting surface) even in a room at 45 degrees it could freeze IF the surface area and cold sides offset the heat influx from the warm sides and allow the tank to get to 32 degree or less.  Possible.

 

In reality the water tank in the campers is usually some kind of polyethelene (not a great thermal conductor) and it is within the heated envelope of the camper.  Further it sits on top of a wood floor (modest insulator) and is enclosed by thin wood sides (weak insulators) with one side typically adjacent to the camper side wall (potential for significant heat loss).   Depending on camper model and year the tank may have more or less heat loss through the side wall and floor.

 

Why not use a thermostat and measure the temp in the water compartment near the back and bottom of the tank (it is important to do this with it empty) while also measuring the temp inside the camper - at the same time.  Do this for several temps above and below 40 degrees after the temp has soaked (or dwelled) to be at a stable temp. The wider the temp range the better. The more data the better,  Plot the data and draw a line (if more then 3 date points fit a curve to it).  You will have a first order idea if keeping the camper at 35 or 40 or 45 degrees is enough to keep the water tank compartment above freezing.

 

This involves some time and effort but it is better than guessing.

 

But if you want to guess I think guessing that keeping the inside of the camper at 45 degrees will likely do the trick (however, 35 or 40 degrees may do the trick too).   ;-)

 

Regards,

 

Craig


Edited by ckent323, 18 January 2016 - 08:19 PM.

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#73 Wallowa

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Posted 18 January 2016 - 11:02 PM


 


Craig,

 

Kinda new that water freezes at 32 F.. :D  But my thought was that the thermostat and heater work in concert to heat inside box of the camper to the set temp and the areas with the plumbing and storage outside that box are subject to much less insulation and therms from the heater.  In short form, at 35 F inside the living area, the -5 F ambient outside may well lower the areas outside that cozy 35F inner box living area to well below 32 F.

 

Good idea on measuring temp differential in differing sections of the camper and then setting the thermostat at whatever is needed to keep water from freezing in the camper's "outer shell area".  So many variables and so little consistence in temps, how and when heat is distributed and how, when and where heat is lost.  In the final hour before dawn the difference in frozen lines and ruptured fixtures may only be the difference in cloud cover or wind velocity changes with variance in back radiation and ambient temps.

 

Proof of the pudding is in the eating; so when in doubt crank up the heat and open access doors and then hope that is enough.

 

Or play it smart and remove all the water from the camper systems.  Carboy inside = coffee in the morning! ;)

 

Phil


Edited by Wallowa, 18 January 2016 - 11:06 PM.

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#74 Stalking Light

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Posted 22 January 2016 - 03:44 PM

Swapped out my White Rodgers for the Honeywell and will see how it works next week, although the real test will probably be in mid Feb when I go to Reelfoot Lake to photograph eagles.

 

Just taking the unit from inside the house into the 40 degree camper showed that the temp reading is more sensitive to quick changes, so I am cautiously optimistic.  :)


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#75 Stalking Light

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Posted 14 February 2016 - 05:18 PM

Just an update, we're camping in 20 degree weather and freezing rain and the Honeywell thermostat is performing admirably and very little latency when warming up the camper from cold. Well worth the few coins.


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#76 melcooke

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Posted 18 January 2022 - 03:14 AM

I think I might try mounting the thermostat with some 1/4" or 1/2" spacers allowing air behind the thermostat.

I'm liking this idea to allow for air circulation and a thermal break from the cabinet. We are certainly living with this issue and plan to continue our stays in resort parking lots with the combination of blankets, window coverings, under bed insulation and the right combination of clothing and bedding layers.


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