Dometic frig works on electric only (but gas burner is lighting!)

[eaglesview01]

We have a 2014 Fuzion toy hauler and the Dometic fridge stopped cooling on a recent camping trip (on electric or gas). Took it to a repair shop and they found nothing wrong. Got it home and it would cool fine on electric but not on gas, even though the burner is lighting and staying lit. Took it back to repair shop for a diagnosis and they still found nothing, however they admitted they only checked that the burner was lighting properly and didn't verify inside temp after it was determined to be cooling properly on electric.

 

[donn]

Thats impossible. Gas and electric use the same stuff except the fuel source. The main board is programmed to select the chealest available fuel source. If the burner is working then the refer will cool. On gas it may take lo ger to cool.

 

[Mark_K5LXP]

Throwing out a WAG, what if the burner flue/chimney is plugged up?

Mark B.
Albuquerque, NM

 

[Henry J Fate]

Yup. Airflow would be my first check. Take the roof vent cover off and with a good flashlight check the vent for clarity. If it is clear, next would be the flame size and location. It would be difficult to offset the flame nozzle so I guess it would be gas volume and flame.

Just to be sure, testing the fridge on gas would require a starting point of room temperature inside the cabinet. Close the doors and fire the gas mode. Place the thermostat to the lowest temperature setting. Let it run undisturbed for 6 hours. Check the inside temps. If it's cooling let it run over night and check it in the morning.

Also I assume you did not watch the flame for 6 hours straight and it is difficult to do that. I would not assume that the flame is in fact staying on. It could be intermittent so keep an eye on that.

Would this problem occur while you are travelling?

One other note...

If you lost cooling on both gas and electric, something common to those two different modes would be the likely cause.

Thermostat
12 volt power
The cooling unit
Control panel
Control board

Those are the things that come to mind. The fridge uses 12 volt power to operate the control panel and other devices. The fridge will not work in any mode without 12 volt power.

 

[Gary RV_Wizard]

I guess it is conceivable the burner "chimney" is blocked somehow, but if the gas is burning the heat is still there. It's possible the flame is too low or being defused, though, I so I'd clean the burner chamber to make sure there are no insect nests in the way.

As donn says, the cooling unit works exactly the same with either gas or electric heat source, so as long as the gas flame provides heat, it should be cooling the same as electric. If the heat flow up and out the upper vent is ok for electric, it's ok for gas mode too.

 

[Mark_K5LXP]

When I first got my RV the refrigerator worked but upon inspection/cleanup big as life there was a wasp nest in the burner assembly. Don't think there'd be much chance they'd have a lot of success making a nest beyond where the flame is and I would think the RV shop would've checked for such things. The wasp nest and a rat nest in the generator were both missed by the pre-purchase "inspector". Troubleshooting 101 is to never assume anything.

Mark B.
Albuquerque, NM

 

[Henry J Fate]

If the heat flow up and out the upper vent is ok for electric, it's ok for gas mode too.

I would disagree with that. The propane mode would command more air flow than the electric element. The heat from the electric will be applied regardless of the air flow. Not true with the propane option.

I would conclude that a blocked vent (full or in part) could exist but I would lean to a nozzle or gas pressure issue but the roof vent cover should be removed and the vent checked.

 

[Kirk]

I guess it is conceivable the burner "chimney" is blocked somehow, but if the gas is burning the heat is still there. It's possible the flame is too low or being defused, though, I so I'd clean the burner chamber to make sure there are no insect nests in the way.

I would disagree with that. The propane mode would command more air flow than the electric element. The heat from the electric will be applied regardless of the air flow. Not true with the propane option.

While I suppose it is possible that a partially blocked flu could cause more problems with propane than electric, it would be very unusual. Like Gary suggests, I would clean the burner area first. If you have a shop vacuum, use the suction of it to remove any debris from it as a quick check. While you are about it, carefully check for anything that might partially block air movement through the cooling unit, from bottom to the top. It is not rare for insulation to move and partially block air movement through the cooling unit and that can cause problems, but very few things would impact the operation on gas and not on electric so be very sure that the burner and flu are clean and clear.

If you would post the model of Dometic refrigerator that you have it would enable us to locate a service manual for it.

 

[Henry J Fate]

Electric elements will supply cooling with a blocked vent because of the way the elements are mounted. Gas burners will not as the flame heat won't get to where it needs and may be heating other areas of the fridge if the air flow is blocked.

Because there is a flame and a repair service confirmed the burner was working and it works on electric, checking the flue for a blockage is not just a functionality issue it is a safety issue.

First step is to verify proper air flow up to the roof. This is a very typical approach based on the symptom and information posted.

 

[eaglesview01]

While I suppose it is possible that a partially blocked flu could cause more problems with propane than electric, it would be very unusual. Like Gary suggests, I would clean the burner area first. If you have a shop vacuum, use the suction of it to remove any debris from it as a quick check. While you are about it, carefully check for anything that might partially block air movement through the cooling unit, from bottom to the top. It is not rare for insulation to move and partially block air movement through the cooling unit and that can cause problems, but very few things would impact the operation on gas and not on electric so be very sure that the burner and flu are clean and clear.

If you would post the model of Dometic refrigerator that you have it would enable us to locate a service manual for it.

Model # DM2862LBFX

Also, I have noticed that the flame sound is not as loud as it was...almost like it's on a pilot light mode?

 

[eaglesview01]

So here's a pic of the top of the chimney...nothing could have gotten in there as it's practically sealed and you can see the insulation is undisturbed. In the last 2 weeks I have started off in electric mode as well as gas mode and every time it cools in electric but not gas (and it is lit). Well the 4th time I started in electric and it did not cool down any after 36 hours!! The camper has not been moved. The pipe going into the bottom of the chimney is warm but the pipe coming out the top was HOT!! Burn to the touch hot. Could the cooling unit be getting blocked?? If so, why so sporadic?

 

[Kirk]

.almost like it's on a pilot light mode?

There is no pilot light on modern absorption refrigerators. They use an electric igniter. Here is a copy of the Dometic service manual that you can download.

Could it be that your propane supply is not at the proper 11" of water column pressure?

 

[Alontheway]

There are other factors unrelated to the boiler that cause fridge to not cool.
Is yours not cooling at all, or just not cooling enough?
Inside the fridge you need to keep the fins clear as these need airflow. Bags pressed against them will cause issues.
Good airflow behind the fridge is needed. If it gets hot back there and stays hot then that heat negates the cooling effect. Many campers experience non-cooling when they park with the fridge side in the sun, but you said "recent" meaning Oct or Sept? What was outside air temp? was your fridge side parked in the sun?
Yes, dirt dobbers and wasp love propane smell. They can cause issues.

Your flame could be coming on, then going off a few minuets later due to gas supply issues. Maybe the ressure builds up when everything is off, then as you use the gas the pressure drops because gas is not able to flow through the system fast enough to keep up. When pressure drops too much the fridge just shuts it down. Check the regulator. However, this is not going to be issue on electric.

That neither gas or electric works suggest that it is not the boiler.

Have you considered that the cooling unit is just trash? IF you run fridge off level too much you will cook the chemicals and they clog up and no longer cool.
Replacement just for the cooling unit is $600 or more. Labor is not cheap or fun.
If the electronics are bad then that is beyond me

 

[Gary RV_Wizard]

He says it cools fine on electric, so the problem has to be the burner.