Propane Camper Fridge

[Coho975]

Wondering if anyone else has run into this. The propane fridge in my camper is not working when I run it on gas. If Im plugged in and running on electric it works great for weeks, so i don't think my refrigerant loop is compromised. When I switch to gas, it will cool off for a day or so and then when I load it and take off, about day two, it will only hold about 50 degrees. Loading it with already cool or frozen food. I've checked/cleaned the orifice, wire brushed the burner tube, verified the solenoid valve is opening via the thermocouple, full tank of LP. Only thing I can think of is the regulator is not supplying enough pressure or the valve is not opening fully. We are at about 6800' elevation, I'm not sure if its a fuel/air ratio problem. Any input or advice would be much appreciated.

 

[Todd]

Is it blowing out when you take off and then not relighting?

Has it ever worked right?

Mine goes to much higher elevations and I don't have any problems.

 

[Ryan]

Try a google search on this problem. There are many discussions.
Also I know dometic had a big recall. Was your fridge included?

 

[Squirrel]

Sounds like it is a “gas thermostat” issue. They are 2 separate control systems, electric & gas. I wrestle with mine when it’s really hot at the lake, on propane. My RV is REALLY OLD. Sq

 

[Coho975]

Is it blowing out when you take off and then not relighting?

Has it ever worked right?

Mine goes to much higher elevations and I don't have any problems.

It will sometimes blow out going down the road (Wyoming), always one of the first things I check when we settle in. It worked great the first two years, this summer started having problems.

 

[Motorboater]

If it’s a dometic, it’s your circuit board. Replaced 2 on different RVs. Don’t replace it with a dometic board. Get the after market board made by dinosaur. Half the cost or less. It has an extra ground wire that helps keep the circuit board from shorting out. Also it has an adjuster to control the temperature in addition to the one already on the fridge. Instead of having to run it on the coldest setting at Powell in the mid summer, you can use the circuit board adjuster then run your fridge on a higher setting and keep it as cold as you want.

 

[Cliff]

OK Here goes-
Dometic's check to see if things are working correctly is to start with the WEATHER and fridge at about 80 degrees or less and put about 1 gallon of room temp water into the food area with the thermometer in it. Close the doors and turn on the gas or electric (which ever you are testing. In @ 4 hrs the water should be 40 degrees or so. IF higher something might be wrong with the system

To test the cooling coils themselves you plug the electric heater leads directly to a 120 volt extension cord and let it run. It should just about freeze the water in the bowl after 24 hrs. If the water is just about frozen or frozen and the freezer above is down near 0 degrees the coils are working and you have a control issue

Control issues-
Dometic says that anything above 5000' will be detrimental on the cooling of the refer as there is not enough oxygen available to produce enough heat from the gas flame (mine sorta works ok at 7300', not great but OK).

Outside air temperature- anything above @ 90 degrees outside and the cooling ability goes down.
If the sun is bearing down on the side of the camper that holds the refer that will be bad for the cooling.
Dometic has an installation manual that shows how the cavity that the refer goes into should be constructed. I have found some camper makers do not follow the install diagram correctly especially on the "draft cavity" behind the refer. If the cavity is too deep no cooling air will pass by the coils in the back at that lowers the cooling ability. Check this out. Air has to go from bottom to top and draw cooler air in to cool the coils. There are many utubes on how to install computer fans in the cavity to help cool the coils.
On the inside of the food box make sure there is space for the cool air from the plates to GRAVITY feed all the way down to the bottom. Don't "pack" the shelves tight or the cooler air can't fall to the bottom. There are also many utubes on how to install a small fan on those plates to move the air around more effectively.
Check to see if you have a "thermistor" mounted on the right side of the cooling plates in the food box. It clips onto one of the plates. Small about 1/4" in diameter. The higher toward the top of the plate it goes the cooler it calls for. It can be checked with a volt/ohm meter for the correct resistance. It can also be disconnected from the circuit board and leave the refer in the "calling for most cold" mode to see if that makes any difference.

The gas pressure AT the fridge needs to be checked at 11 inches of water coulomb pressure. There is a test hole plug in the gas line of the fridge for this check. I found on trailer that had a clogged delivery line to the refer letting only very little gas flow. On another I found that it had a filter inline just before the burner that was clogged

Check the "look" of your flame and how high it goes. On the clogged filter one I had the flame was clean and blue but very low (no heat).

Other items to check-
The dollar bill seal check. Close the door with a dollar bill in the seal and move it all the way around the door to see if the seal causes drag on the dollar bill. That means the seal is tight.
Most refers have a drain in the food box in the back that lets condensate water out of the box to the outside in back of the fridge. The hose in the back of the fridge (accessible through the door on the outside back of the unit) should have a small button in the end of the hose with small holes in it to keep bugs out and also to limit the amount of hot outside air from going back up the hose to the inside of the fridge. This alone can raise your food box temp 10 degrees.

It may turn out that the altitude you are at might be your biggest issue with cooling on gas. That and packing the food too tight in the box.

Have you tried the gas at a lower altitude to see if it works there? On my brand new refer at 7300' I get down to 40 degrees in the food box. I'm working to improve that this winter with fans and a "clip tip" thermistor. I added frozen water bottles to my food box and it helped for 3 days until the ice melted in the bottles.

 

[Coho975]

OK Here goes-
Dometic's check to see if things are working correctly is to start with the WEATHER and fridge at about 80 degrees or less and put about 1 gallon of room temp water into the food area with the thermometer in it. Close the doors and turn on the gas or electric (which ever you are testing. In @ 4 hrs the water should be 40 degrees or so. IF higher something might be wrong with the system

To test the cooling coils themselves you plug the electric heater leads directly to a 120 volt extension cord and let it run. It should just about freeze the water in the bowl after 24 hrs. If the water is just about frozen or frozen and the freezer above is down near 0 degrees the coils are working and you have a control issue

Control issues-
Dometic says that anything above 5000' will be detrimental on the cooling of the refer as there is not enough oxygen available to produce enough heat from the gas flame (mine sorta works ok at 7300', not great but OK).

Outside air temperature- anything above @ 90 degrees outside and the cooling ability goes down.
If the sun is bearing down on the side of the camper that holds the refer that will be bad for the cooling.
Dometic has an installation manual that shows how the cavity that the refer goes into should be constructed. I have found some camper makers do not follow the install diagram correctly especially on the "draft cavity" behind the refer. If the cavity is too deep no cooling air will pass by the coils in the back at that lowers the cooling ability. Check this out. Air has to go from bottom to top and draw cooler air in to cool the coils. There are many utubes on how to install computer fans in the cavity to help cool the coils.
On the inside of the food box make sure there is space for the cool air from the plates to GRAVITY feed all the way down to the bottom. Don't "pack" the shelves tight or the cooler air can't fall to the bottom. There are also many utubes on how to install a small fan on those plates to move the air around more effectively.
Check to see if you have a "thermistor" mounted on the right side of the cooling plates in the food box. It clips onto one of the plates. Small about 1/4" in diameter. The higher toward the top of the plate it goes the cooler it calls for. It can be checked with a volt/ohm meter for the correct resistance. It can also be disconnected from the circuit board and leave the refer in the "calling for most cold" mode to see if that makes any difference.

The gas pressure AT the fridge needs to be checked at 11 inches of water coulomb pressure. There is a test hole plug in the gas line of the fridge for this check. I found on trailer that had a clogged delivery line to the refer letting only very little gas flow. On another I found that it had a filter inline just before the burner that was clogged

Check the "look" of your flame and how high it goes. On the clogged filter one I had the flame was clean and blue but very low (no heat).

Other items to check-
The dollar bill seal check. Close the door with a dollar bill in the seal and move it all the way around the door to see if the seal causes drag on the dollar bill. That means the seal is tight.
Most refers have a drain in the food box in the back that lets condensate water out of the box to the outside in back of the fridge. The hose in the back of the fridge (accessible through the door on the outside back of the unit) should have a small button in the end of the hose with small holes in it to keep bugs out and also to limit the amount of hot outside air from going back up the hose to the inside of the fridge. This alone can raise your food box temp 10 degrees.

It may turn out that the altitude you are at might be your biggest issue with cooling on gas. That and packing the food too tight in the box.

Have you tried the gas at a lower altitude to see if it works there? On my brand new refer at 7300' I get down to 40 degrees in the food box. I'm working to improve that this winter with fans and a "clip tip" thermistor. I added frozen water bottles to my food box and it helped for 3 days until the ice melted in the bottles.

Great write up Cliff, lots of good advice. Thank you. Looks like this weekends project.