Problem with a 6 year old Dometic frig

I have a Dometic 4 door. Big one. Our second one. First died after 6 years & in excess of 700 nights use.

Second appears to be dead after 10 years & 1700 nights on the road use. Tried the cheap way first. Replaced the thermistor. No luck. Can't see spending serious money on a 10 year old fridge that has been bounced around for so many miles.

We have also looked at residential fridges, much cheaper, but there is the problem with fit. Residentials work well for seasonal RVers sitting in one spot all summer. Not so good for travellers who will need a decent sized battery bank & inverter while on the road & will more or less be limited to CGs with power.

larry cad wrote:
Friend of mine has a class C with a Dometic frig not working. We did some investigating yesterday, and found the following:

Propane flame works when in that mode

Electric heat works when in that mode

Frig temperature doesn't change in either mode and stays constantly at 51

My conclusion is the frig is broke and needs a new cooling unit, or am I missing something?

BTW, my suggestion to him was to install a residential unit instead.

Outdoor temperature? Freezer temperature? Have you checked the cooling fans in the back?

larry cad wrote:
Friend of mine has a class C with a Dometic frig not working. We did some investigating yesterday, and found the following:

Propane flame works when in that mode

Electric heat works when in that mode

Frig temperature doesn't change in either mode and stays constantly at 51

My conclusion is the frig is broke and needs a new cooling unit, or am I missing something?

Maybe try this first. It can be hard to conclude that no cooling on gas or electric is the cooling coil. It might be, but there are other things that can cause that issue a lot cheaper to fix.

Try these:

With fridge off,

Go outside and take the lower vent side panel off. Sniff and look for yellow residue near the gas burner area. You may have to remove a shield but you need to see the gas burner with no cover on it if yellow stuff is not yet visible. If there is residue, the cooling coil has a leak and it may smell like ammonia. If there is no yellow residue and no strong smells after seeing the gas burner, then try this next step as leaks do happen in other areas but maybe more often in the gas burner area. The last one I dealt with where the coil went out, I had to remove the gas burner shield and then saw it.

If no yellow stuff yet, then turn on fridge on electric, or gas, make sure the light inside the fridge works and the control lights are on for normal. No lights that is a problem.

Go outside and look at the gas burner area again, if on gas, is the burner lit and the system heating? If on electric, you may have to wait 1/2 hr and then gently feel for heat on the boiler sheet metal, is it getting hot?

If you have no heating in the boiler area on gas or electric, then there is a controller issue as problem one. You then have to back into why.

If it is heating, after about 3 hours of running, the inside temp should be dropping. Confirm this with a thermometer inside the fridge from when it started until the end of the 3 hr period. There should be some good level of temp drop.

If it has been heating constant for 3 hours and nothing happens to drop the temp inside, not even 5 degrees, then this points to the cooling coil.

Hope this helps

John

If after an hour or two the boiler stack feels warm/hot but you are getting no cooling in the freezer or refrigerator, it is most likely your cooling unit.

If you are handy and a DIYer, replacing the cooling unit isn't too hard. Plenty of videos online.

Going to a residential fridge may or may not be a good idea for your friend, depending on HOW/WHERE they camp (hookups or no hookups) and what sort of battery bank (and solar) they have.

Good luck!
Chris

larry cad wrote:

My conclusion is the frig is broke and needs a new cooling unit, or am I missing something?

BTW, my suggestion to him was to install a residential unit instead.

First a suggestion.. Look for a brown or yellow stain or powder lower right outside compartment.. If you see it I'd say odds your conclusion is spot on.

Now your recommendation,,, Not that keen on Residential units in an RV.
Reason: Long drive.. No power..No cold
Power fail: No cold (I was camping one day when Digger O'Neal and his back hoe sliced the primary (ZAAAAAPPPP lights out)

NOW: a somoehat expensive but very good alternative is what I call a "Danfoss class" Both Dometic and Norcold have made them Just now I could not find them but they draw in the range of 50 watts.

This one 150
https://parts.unitedrv.com/products/dometic-10-cu-ft-12-volt-dc-refrigerator-dmc4101?variant=39973672779864&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&srsltid=AYJSbAdBhXW740JBkGHOTG7ZfCgC710hkJH1rV02g1WDhvoTILnrjt0zBYk

Step one

Shut the unit down for two full days
Then restart

What happens?

If the cooling unit has failed, you might consider a 12 volt compressor replacement cooling unit.
We just did this change and could not be happier. Consistent refer and freezer temps, hard ice cream in the freezer and quick cool down.
We got ours from JC Refrigeration

The temperature readings I quoted are from the digital thermometer above the freezer door on the frig itself. The ambient temperature outside was low 50s daytime and mid 30s at night. Tried running on 120v first, and for a couple days. Temp on frig read 51. Then ran on propane, with same results. I have not smelled ammonia, nor have I seen yellow powder. Fans are working.

I guess I should say the temps varied from 51 to 53 with the above stated ambient air


Regarding replacement, he is looking at the 12V compressor option as well as residential. His class C has a generator and he doesn't mind running it, so a residential is a viable option. I personally have never liked the evaporator type frig despite it's stated advantages.

Thanks for all the help and suggestions.

wa8yxm wrote:

larry cad wrote:

My conclusion is the frig is broke and needs a new cooling unit, or am I missing something?

BTW, my suggestion to him was to install a residential unit instead.

First a suggestion.. Look for a brown or yellow stain or powder lower right outside compartment.. If you see it I'd say odds your conclusion is spot on.

Now your recommendation,,, Not that keen on Residential units in an RV.
Reason: Long drive.. No power..No cold
Power fail: No cold (I was camping one day when Digger O'Neal and his back hoe sliced the primary (ZAAAAAPPPP lights out)

NOW: a somoehat expensive but very good alternative is what I call a "Danfoss class" Both Dometic and Norcold have made them Just now I could not find them but they draw in the range of 50 watts.

This one 150
https://parts.unitedrv.com/products/dometic-10-cu-ft-12-volt-dc-refrigerator-dmc4101?variant=39973672779864¤cy=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&srsltid=AYJSbAdBhXW740JBkGHOTG7ZfCgC710hkJH1rV02g1WDhvoTILnrjt0zBYk

Regarding 12v refrigerators like the one listed above, can anyone comment on how many AH/day they tend to use? I'm just curious. I'm not really looking to switch as my refrigerators are working on my RVs, but if they die I would like to know more about 12v fridges. My RVs have more than enough solar for my current needs, so perhaps they can handle a 12v fridge also.

-Chris