javaseuf wrote: I wonder if the heater is energised when on gas. If it is, I'd be splicing a switch in series with that sucker so I could turn it off.
On mine it explictly says it's on when the refer is on, except when defrosting. I read that to mean that it's on even when running on gas. I don't see any specs on it, I wonder how much current it takes? I might have to get my meter out and start making some measurements.
2007 Holiday Rambler Endeavor 40PDQ 400 ISL Cummins/Allison
2002 Chevy Avalanche toad
Inside: Him, Her, and a pack of little furballs...
LLeopold wrote: 2-way RV fridges operate using one of two power sources for heating the ammonia solution used for cooling the interior:
1) 120VAC, or
2) Propane
The control board itself requires 12VDC from the house batteries and/or converter to run. If your house batteries are low and you are not on AC to run the converter, your fridge will not operate, even if you have full propane tanks.
The Auto mode puts the fridge to detect if electricity is available and, if so, to "favor" using the AC heating element over the propane burner.
The Propane mode overrides the sensing and uses only propane for
heati
The moisture control switch operates a purely electric (120VAC) heating element (if available)
Hope this helps.
Re Moisture Control: you say "purely electric 120 vac heating element...
We like to boondock this time of year, but we need the furnace some at night. I think my fridge (norcold in a 2006 Duthcman 258gl) is using the DC to keep moisture control working. I cant get more than one night from my group 24 battery.
Testing here at home I have run the furnace for two nights WITHOUT the refer on and the battery is still very high.
I have called manufacturer and they say I cant turn off the refer heater but I did not think to ask if it was DC or AC or both.
I just turned the refer on GAS ONLY...lets see if that changes things. Maybe if it is GAS ONLY it wont use the refer heater.
Moisture reduction heater:
The refrigerator has a heater that prevents moisture from forming on the center divider between the doors of the freezer and the fresh food compartment. The heater operates only when the refrigerator is ON.
Looking at the wiring diagram, these fridges use a DC heater. If you have the type that has a moisture control switch that has normal, off, high moisture positions, off turns off the fridge completely for storage. The other two positions will use DC power for moisture control. Apparently, it cannot be turned off in 2-way fridges unless the fridge, itself, is turned off.
Upon closer investigation of the Dometic Owner's Manual, I found the following (emphasis mine):
G. CLIMATE CONTROL
During the summer months of high temperatures and humidity, the metal frame between the freezer and fresh food compartments may have water droplets forming. The number of water droplets will increase if the vehicle isn't air conditioned during these months.
This refrigerator comes standard with a 12 volt (DC) climate control that will evaporate the water droplets when they form.
To have the climate control on, you position the switch ("C", Figure 10) located beneath the top decorative strip that houses the control panel to ON. The climate control can be left on continuously or only used when temperatures require it.
CAUTION
THE CLIMATE CONTROL WILL DRAW 12 VOLT DC POWER CONTINUOUSLY WHEN IN THE "ON" POSITION. IT SHOULD BE TURNED "OFF" WHEN A CHARGING SOURCE IS NOT AVAILABLE. IT WILL QUICKLY DRAIN THE CHARGE FROM A BATTERY.
Hope this helps and sorry for the initial misinformation.
* This post was
edited 10/28/07 06:08pm by LLeopold *
Lou Leopold
2001 Dodge Ram 2500 Diesel Quad, SWB, 3.55:1, Rhino Lining
2000 25' Mallard M-23 5M 5th Wheel
Husky 15K w/EZ slider
Wen PowerPro 3500 Generator in a sound box
And I continue to tent camp!
You have to open the door of the freezer to find the switch to the climate control on our Dometic. It is below the other controls, but as I remember, it's on the underside of the top of the freezer frame, so you have to look UP to find it. We were dry camping for the first time about 10 days ago, so I read the frig manual to find out how to conserve our battery. It wasn't clear in the manual, but I assumed that changing from AUTO to GAS might decrease battery drain.
smkettner wrote: To minimize the 12 volt battery power used put the fridge to Propane setting, not the Auto setting. Also if there is a humidity control turn it off.
Why does the auto setting use more power? I would think the board is powered either way.
Well I had read this and believed it. When you called me on it I just did not know for certain so I recently measured it.
My trailer draws 175 milliamps minimum to run the propane detector and the radio memory while turned off. Turned the fridge on propane setting and the total draw was 510 milliamps so the fridge was pulling 335 milliamps while igniting. Once lit the total was 487 so the fridge was drawing 312 milliamps.
Now the big test I switched it over to Auto setting from Gas. The draw went to 494 milliamps or a whopping 7 milliamps. I think that must be just the indicator light. So the conclusion is that on my fridge the setting from gas to auto does not take any significant power.
I did find it informative that my trailer takes basically 1/2 amp minimum to run with the fridge flame on. Battery voltage was at 13.1 during the test.
2001 F150 SuperCrew 5.4 Lariat Offroad 4x4 Tow Package 4.10 Truetrac
2006 Keystone Springdale 249FWBHLS
12K SuperGlide, KGE3000Ti 2.3kw rated 2.6kw max
Frank's voltage booster, Prosine 1800 powered by 4 GC2 batteries
smkettner wrote: Now the big test I switched it over to Auto setting from Gas. The draw went to 494 milliamps or a whopping 7 milliamps. I think that must be just the indicator light. So the conclusion is that on my fridge the setting from gas to auto does not take any significant power.
That sounds about right to me. A few milliamps to light the auto indicator, but that should be about it. An increase of 1.4%, hardly worth worrying about. A 7 milliamp draw on the battery is nothing, it will have no material effect on it's life. The normal parasitic draw on the battery is probably larger than that.
I make my living programming the embedded software on various types of controller boards. While I've never worked on an RV fridge controller board, I would be very surprised if the auto mode took any more power than any other mode (except for the indicator light, as mentioned above.) All that is really necessary is an input where the microprocessor can monitor the AC voltage, and a few lines of software. That input is going to be powered up and running regardless of the mode. The only difference is that in Auto mode, the microprocessor will look at that input, and if active, it will turn off the gas and turn on the AC heater. (At least that's the way I would design it, as it seems like the simplest and most straight-forward method.)
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