Older Dometic Refrigerator Cools intermittently

Hello all!

First, the facts:
Fridge is a Dometic RM2807, presumably from 1994 as I don't think it's been changed out since the rig was built. Dual fuel (gas & 110).
Has worked more-or-less great for the past 6 months. Occasionally we'd wake up and it'd be a little warm, but flicking it off for a minute and back on always solved it. I chalked it up to old age.

But yesterday it got warm outside, and the fridge got warm inside. I've tested everything I can think of, and I 'suspect' it might be a system issue, but wanted to post here before I either begin the hunt for a new fridge, or dump $500 on a remanufactured system and spend a day installing it. (according to the records I have, the previous owner actually replaced the cooling system in '03)

What I've done/know:
Tested Thermister, returns ~4K ohms at room temp, seems close to the specs I could find (though I have yet to find any documentation on this specific model)
Confirmed that the LP is on, there's spark, and it lights consistently (I actually think the thermocouple might be needing replaced as it continues to spark now and then even when lit)
Confirmed power to 110 heating element (though I usually run it on propane)
No ammonia smell or yellow powder present.
No rat's/bird's nests underneath or behind the fridge.
There is a vent on top of the RV

Things I don't know/haven't done:
Don't know if there's a ventilation fan, or if there could be a nest somewhere I can't see restricting airflow.
I haven't accessed the rooftop vent as the RV doesn't have a built-in ladder, and I don't have access to one at the moment.
I haven't confirmed that the 110v heating element is good or bad, but as I basically always run on LP it hasn't really mattered.

Anyway, it's a decently large fridge (2' x 2' x 5'), so if I can avoid replacing it, that'd be great! However, I know that everything has it's time, and I don't really want to just throw a bandage on a gaping wound if this guy is really toast.

Thanks!
Paul

Welcome to the Forum!

Thank you for a great break down of what you have checked so far!  I'm not used to this!
Even if the cooling unit was replaced in '03, that still makes it 15 years old.  But it does not have the chassis failure signs.

How are you using the camper, weekend trips? Full time?  Do you frequently tow it or is set up on a lot?  If it is on a lot, especially if you are full time, you may want to consider a residential refrigerator for a replacement.

Hopefully, the refrigerator experts will be here soon!

Howdy Grashley!

I try to keep myself organized (only way I can survive ), and save y'all the time of asking me all the little things!

To answer your question, yes, we're full time so it's basically on 100% of the time. Hmm, I hadn't thought about that being an issue, though given it's age and the fact that absorption probably doesn't have the stamina that a residential does, that might be what I need to do.

So in that vein of thinking, are there certain residential fridge brands that are more well-suited to RV life? Oh, and are there any that run on propane? (we're probably only plugged in 60% of the time, and only have an 1,800w inverter)

Paul

I would suggest checking every electrical connection you can get to.  There's bound to be some corrosion present.

The flame may be weak.  Even a tiny obstruction is enough to weaken the flame.  Less heat = less cooling.  Also may be the cause of the extra sparking.

Get the service manual for your 2807 here:  http://bryantrv.com/docs2/docs/servtips.pdf

Some further questions:
Is the cooling (temperatures) the same in LP or electric modes?  What are the temperatures in freezer and fridge sections?  Running a little warmer than usual, or barely cooling at all?

It's not unusual for an old cooling unit to develop a pin hole leak from corrosion. The hydrogen  gas in the coolant leaks out and cooling is seriously degraded, usually showing up as a loss of cooling in the fridge section while the freezer still works.  However, I'm not sure your 2807 has two-stage cooling with separate chill-plates for the freezer & fridge.

If the cooling action is the same on both LP and electric, you can rule out a lot of variables, like poor gas flame or faulty electric heat element.  And if the burner stays lit, trying to cool, you can ignore the thermister and related control functions - the fridge is trying to cool so the thermister has done its job.

I have the same refrigerator. It always cooled better on propane. About every 3 years, rust and crud would disrupt the flame. Sometimes flame would go out for no reason. I just take cover off (1screw) and blow out burner. Then I have a nice blue flame and no problems for another 3-4 years. Easy to remove cover and see what your flame looks like. Oh, and I always tap on vent pipe while cleaning burner to get a the loose stuff that?s ready to fall. If you don?t have an air compressor, canned air would work or maybe vacuum.

Ok, sorry for the delay, traveling for work.

Thanks Gary RV_Wizard for the manual! I looked and looked but couldn't find it. That's why you guys are the experts.

With the knowledge gleaned from it I was able to test the AC heater coil and confirm that it's shorted out, so that's good to know, but still doesn't explain my no-cooling problem on propane.

Also, it appears to be a two-stage cooling system, there's fins in the refrigerator compartment (with a thermistor on it), as well as a cooling plate in the middle of the freezer.

Jubileee, I tried you suggestion and cleaned out the flame grill, ports, all that as best as I could. I think there was 'some' improvement in flame size, but nothing particularly dramatic. I've attached a photo of what the flame looks like.

Even though I'm not detecting any powdery residue or ammonia smell, do y'all think I probably just have a bad cooling unit? If so, I feel confident in my skills to replace it, but I wonder if a better route wouldn't be to buy either a used Dometic, or go residential?

Paul

I have the same 2807 in my 95 Bounder. I have had igniter failure and flame detector failure. Other than that, it has been flawless. Wellllllllll, I have to clean the burner and stack every once in a while. They all need that.
Replace the electric heating element and hook it directly to an extension cord. That takes all the controls out of the scenario. If it works well that way, you have a control problem to find.

I have a 1990 class C with the original norcold refrigerator. I had to take the entire contol unit apart behind the control panel inside. There were some loose quick connect terminals which I fixed by pinching with a pliers, The thermocouple was a little loose behind it, and I also had to use a few small wrenches and recalibrate the control unit. Right now, I have it cranked up and it is just cold enough, but it beats $1000 on a new unit.

I recently found out that there is an RV salvage yard nearby. One of these days, I would like to go look for a better furnace and see how much they want for another refrigerator.

Finally circling back around to solve the fridge issue. We've been on the road (and broke ) for the past couple months so I haven't been able to devote time to research (or money to the spending).

Given that the issue seems to be narrowed down to the absorption system which is a $500 repair and then I'm still left with a 20 year old fridge. For double the price I can replace the entire fridge and increase the resale value.

So, thoughts on the new Dometic compressor refrigerators? Specifically the Dometic DMC2841? It is the closest fit to my current 2807.

Otherwise, I'm considering the Dometic 2852.

Paul

Also, any recommendations on the best place to buy RV fridges? Camping world is an obvious choice, but possibly not the best? I'll do the instal if I can, so just a place to buy it.

Paul

leavittontheroad said:

Also, any recommendations on the best place to buy RV fridges? Camping world is an obvious choice, but possibly not the best? I'll do the instal if I can, so just a place to buy it.

Paul

Click to expand...

Google your area for RV supplies.  Camping World will probably be your most expensive option.  Amazon is always an option 

I think you may also require an INVerter (12V DC to 120V AC) to enable running a compressor fridge and a sufficient battery bank unless they run on 12V alone! Just something to check out before deciding.