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Ask Dave: Weird: Only RV freezer works on LP gas, not fridge itself

Dear Dave,
My Dometic fridge works on 120 current but only the freezer works on gas. I’ve replaced the circuit board and the front “eyebrow” board with no luck. I’ve checked all connections and fuses and all are good. Any ideas? —Mike, 2017 Coachman

Dear Mike,
If both the freezer and refrigerator work when plugged into 120-volt power, then we can eliminate the cooling unit being plugged or not working. It would typically eliminate the thermistor, as well. However, I would like to compare temperatures when it is running on 120 volt and then just the freezer on LP.

I assume when you are running the refrigerator on LP it is not plugged into shoreline power, otherwise it would be running on 120-volt power.

Plug into shoreline power

The first thing I would try is plugging into shoreline power and switching your fridge from Auto to LP. Most absorption refrigerators have the Auto feature, which is a default setting to run on 120-volt power. If the power goes off at the pedestal, it will automatically switch to LP and then back if power comes back on. This is designed to keep the fridge cold if you are sightseeing and can’t manually switch it.

If you manually switch to LP mode when it is plugged in and the fridge section starts to work, then it’s a 12-volt house battery issue. I have seen this several times. The batteries get sulfated and seem to be providing power, only to nosedive when lights or other 12-volt operations are drawing power.

It’s also possible the cooling unit starts to work and would cool down the freezer section first, then the drop in power would shut the unit off and not cool the refrigerator section. When you are plugged into a campground source, the converter in your rig will provide 13.6 volts until the batteries reach 12.6 volts, and then drop to a maintenance of 13.2 volts. So, you should always have enough power. If you do not have the option to plug it in, get a portable battery booster and connect that to the house batteries.

Check the Dometic fridge flame

If it does not work with the unit plugged in, then we need to isolate the burner assembly and flame. Once again, I would like to have an actual temperature reading of the freezer to verify it is down in the 0-degree range or close.

Take a look at your flame through the peekhole in the back of the refrigerator compartment. This is done from the outside by taking off the vent cover and sliding the tab that covers it. You can see it here on the back of this unit in the lower right.

The flame should be a consistent blue and not jumping around or have orange tips anywhere. It is possible the flame is not getting hot enough due to blockage in the burner assembly or LP pressure due to a weak regulator.

I would get an air compressor with an air gun and blow out the burner assembly and the coils themselves to make sure all the dust, soot, and any blockage is removed. You will want to remove the metal “box” or covering to get at this and inspect. There could also be a baffle that needs to be cleaned and properly installed.

I have seen cases where the baffle rod broke off the top of the chimney and fell inside. Sometimes even construction materials fall down the chimney. Typically, in these cases, the Dometic fridge needs to be removed to access the chimney from the back.

So, I believe it is either a weak flame and you would need to have the pressure tested by a certified technician, or a blockage somewhere.

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.

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Dr4Film
14 days ago

The cooling unit on the rear of a RV fridge is ONE complete continuous piece of tubing. It is not separated into two areas like residential fridges are where the fridge has one control and the freezer has another control. If the fridge works fine when hooked up to shore power and is running on 120 VAC BUT it doesn’t work correctly when on LPG then you should be looking closer at the propane part of the system. Personally, I would remove the RV fridge and take it to the dump! Then purchase a small 120 VAC fridge that fits into the same space. This suggestion is for RV’s that have an Inverter and a House Battery Bank that can support the fridge while driving.

bill
14 days ago
Reply to  Dr4Film

I’ve had Dometic 6 c.f. fridge units in 5 different RVs over the last 40+ years with no issues. 2 of the rigs were over 20 years old when we traded them.

Wayne C
13 days ago
Reply to  Dr4Film

And be tethered to the grid

Bob M
14 days ago

Dometic refrigerators are a nightmare, I’d never buy another RV with one. Had a travel trailer even the Dometic Fridge technician couldn’t figure out how to repair. Dometics answer to just buy another fridge was unacceptable in a three year old travel trailer.

Wayne C
14 days ago
Reply to  Bob M

I’m surprised at your comment. I’ve had four Dometic refrigerators in various RVs and they have been the most reliable appliance in all of the rigs and have all performed well. They were all 8 cubic feet or less so maybe that’s a factor.

Charlie Sullivan
14 days ago
Reply to  Bob M

I agree with Wayne C. We bought our LTV new in 2013 and it came with the Dometic 3-way refrigerator. It has run flawlessly since and had no problem switching between electric, battery or gas. We keep it set at 4 (one setting below the coldest setting), and it cools perfectly. Maybe we’re just lucky but it’s worked for 9 years without issue.

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