Fridge questions

[RVfixer]

Fridge questions:

I have a Dometic DM2652RBX gas/electric refrigerator in my travel trailer. It has failed and left me needing a new fridge or a replacement cooling unit...I prefer a new fridge, but will look into both options.

The failure mode is confusing to me and presents a couple of questions. I had run the fridge on electric for 3 days at home and loaded it with cold and frozen items. The trailer was dead level in my driveway. We drove 150 miles to camp with the fridge running on propane. At camp the fridge switched to electric operation normally when I plugged into shore power. About an hour later I noticed the Auto light was out on the fridge panel.

Here is my troubleshooting:

Auto light went out, no help pressing fridge function buttons. Door light out also.

Circuit breakers and fuses in the trailer panels checked good (checked properly, not just visually).

Removed outside cover and smelled ammonia...not real strong but ammonia for sure. Also observed a yellowish white stain down wall behind gas burner.

I knew then that the cooling unit was a done deal.Checked the fan inline fuse, checked good with meter, Checked the two fuses in the power module, checked good with meter. 

118 VAC read at outlet that the fridge plugs into, 12.9 VDC read at DC block connection at back of fridge.

Info: This fridge is 10 years old. My last trailer was traded in at 15 years and the fridge looked new and was working great. I do the fridge maintenance at least once a year and always have the fridge level when operating stationary. 

Questions: Why would a cooling unit leak failure result in no control panel lights on the fridge and no door light? All fuses and breakers check good and both power sources are present.

This is kind of an abstract question; My last trailer's fridge was used mostly on external electric power over 15 years. I watch my line voltage and don't run on low voltage. This present trailer fridge has been used on gas operation stationary at least 2+ months every year, plus about the same amount of traveling on gas operation that the last trailer saw. The question is; Is the gas mode (Flame) harder on the cooling unit than heating with the electric coil and could that have contributed to the cooling unit failure? I sent this info and questions to Dometic along with asking what fridge options Dometic has with the same fit and function as the DM2652RBX fridge?  Got an auto reply that they will respond within 72 hours.

 

[donn]

They do fail.  Corrosion and or rust will cause leaks.  Thr Amish cooling units seem to be the best option and for around 700 dollars might be worthwhile if your handy.  As an alternative you might check 12V compressor refers that are far superior.  They may also be out of your price range, but worth a look.

 

[John From Detroit]

All lights out may not need replacement.

My first guess, and I stress Guess, is that the either "Eyebrow" (The part with the lights and buttons) and the controls) has lost communication with the control board outside  -OR- You lost 12 volts.

Using a volt meter or test light and be careful here. Go outside and look for the 12 volt leads.. Make sure they are good and 12 voltish (bright test light) if there is a fuse.. Check both ends
NOTE there is a terminal board bottom dead  center on mine This is a Suspect but I beileve it has both 120 and 12 volts so be careful
Next on mine the "Mother board" is to the left in a black box which contains.. You guessed it. MORE FUSES.

Finally the cable that runs up to the top (multi pin the bigger multi pin) Unplug and replug 4 or 5 times.  then pull the eyebrow (it just pulls off toward you and do the same on that end of the cable.

Try again.

If this works  Think about Lotto tickets
Either "When you hot you hot"
or "I used up all my luck this week"

 

[Gary RV_Wizard]

If you are lucky, a fuse on the controller board has blown. If so, a new cooling unit is all you need. Not cheap, but a lot less than a new fridge and not a hard job to DIY.

Download the Service Tips manual for this fridge and do the checks it prescribes.

http://bryantrv.com/docs2/docs/1252service.pdf

 

[donn]

All lights out may not need replacement.

My first guess, and I stress Guess, is that the either "Eyebrow" (The part with the lights and buttons) and the controls) has lost communication with the control board outside  -OR- You lost 12 volts.

Using a volt meter or test light and be careful here. Go outside and look for the 12 volt leads.. Make sure they are good and 12 voltish (bright test light) if there is a fuse.. Check both ends
NOTE there is a terminal board bottom dead  center on mine This is a Suspect but I beileve it has both 120 and 12 volts so be careful
Next on mine the "Mother board" is to the left in a black box which contains.. You guessed it. MORE FUSES.

Finally the cable that runs up to the top (multi pin the bigger multi pin) Unplug and replug 4 or 5 times.  then pull the eyebrow (it just pulls off toward you and do the same on that end of the cable.

Try again.

If this works  Think about Lotto tickets
Either "When you hot you hot"
or "I used up all my luck this week"

The OP mentioned ammonia smell.  Lights out has little to do with a bad cooling unit.

 

[Gary RV_Wizard]

Yeah, but lights out means there is a 12v problem in addition to the failed cooling unit.

 

[donn]

Troubleshooting 101 fix the most glaring things first.  Yea, no 12VDC means no refer.  But thats probably an easy fix.  Loose wire or fuse come to mind.  We know the OP says he smelled ammonia, so we know the refer is DOA.  Getting 12VDC srill wont do anything.  Like I said before his best option would be a new 12DC compressor refer.

 

[RVfixer]

Thanks for the replies. On my post I included: No cooling. no lights, 120 VAC and 12 VDC present in the locations per my post and I smelled ammonia. I concur the cooling unit is dead. I don't want to buy a cooling unit until I understand why I am loosing power somewhere. I am also curious why these two separate functions happened at the same time..??  Power module (that's what Dometic calls it) AKA controller, control board, circuit board all the same thing. When I get time I have to research and see where to check for power on the power module itself and where to check that power is going to the panel on the fridge face. Heck of a coincidence that the cooling unit leaked AND the panel on the front of the fridge and door light lost power at the same time that the cooling unit leaked.

The 120 VAC is present where the fridge plugs into an outlet, The 12 VDC is present at the connection block at the bottom center on the back of the fridge. Those are the only places I have checked for power so far.

I have read reviews where people had and easy time replacing a cooling unit and many others where they had to do a LOT of forcing and several broke the plastic inside the fridge where the fins go through into the box. Anybody changed a cooling unit that can comment on their experience?

The Amish unit site is advertising $545 for a rebuilt unit and $100 rebate if you send the old unit back free in their box. Here is the hook (for me). If your model fridge has RBX on the PN (mine does) they will not rebate and don't rebuild those because (they say) that unit in not made by Dometic. My question would be if there is a problem installing a factory reconditioned unit as a replacement for a noon Dometic built cooling unit. So I have some research to do.

A side story: We had made a lot of frozen meals to take in the trailer and wanted to stay out of restaurants as we are high risk for surviving COVID. We arrived at the KOA at Natural Bridge/Lexington in Virginia and the fridge quit within an hour of setting up. The campground office saved our trip there! They loaned us a large ice chest to keep items cool at the trailer and had us put our frozen meals in their freezer. We stayed for our whole reservation and had a good time. We canceled our reservation at a second campground and came home. I bought a Styrofoam cooler and ice and got all of our frozen leftover meals home still frozen.

 

[Great Horned Owl]

Troubleshooting 101 fix the most glaring things first.  Yea, no 12VDC means no refer.  But thats probably an easy fix.  Loose wire or fuse come to mind.  We know the OP says he smelled ammonia, so we know the refer is DOA.  Getting 12VDC srill wont do anything.  Like I said before his best option would be a new 12DC compressor refer.

A 12DC compressor refer is only a "the best" option for people who don't boondock for weeks at a time.

Joel

 

[John From Detroit]

Troubleshooting 101 fix the most glaring things first.  Yea, no 12VDC means no refer.  But thats probably an easy fix.  Loose wire or fuse come to mind.  We know the OP says he smelled ammonia, so we know the refer is DOA.  Getting 12VDC srill wont do anything.  Like I said before his best option would be a new 12DC compressor refer.

I missed the ammonia comment. Sorry..  When mine failed I did NOT smell ammonia. but I do know the Amish Cooling unit was my solution.. and sadly it outlasted the RV (soon a scrap yard will have a very good one only a year old on hand)

 

[Gary RV_Wizard]

I can understand your reluctance to repair when it had a double-fail, but the replacement model (RM 3762) is around $1400, plus whatever you do for installation.  Would probably cost you $3500 or more at an RV dealer.  BTW, Dometic fridges & parts are in limited supply right now, supposedly because of pandemic reasons.


What about a 6-7 cubic foot dorm or apartment-size fridge (120v only). Would that work for your needs? Many people are forsaking the traditional 2-way RV fridge.

 

[RVfixer]

Gary

We do a lot of camping at National parks. We do a month in the spring and a month in the fall with the fridge on gas operation. We do a lot of hiking and only get around to charging our batteries every couple of days in the limited allowed generator hours. So, I prefer to fix this fridge or replace it with one that will fit the cabinet without modifications. They don't make this exact model any longer but there are other models with the same fit and function. However, I have found the exact same model as mine online new for a little over $1200 at a couple of places. I have emails in to two RV dealers and Dometic with various questions and am awaiting replies. If I don't get any replies in a day or two I'll start calling or visiting shops. We aren't in a big hurry.....but soon it will be decision time.

I would like to find a local dealer that will sell and install a new unit or one where I supply the new fridge, or a shop to replace the cooling unit in my fridge..."at a reasonable price to me"...I know, I am likely dreaming. Alternately, I could replace the cooling unit myself or install a new fridge myself. Due to a temporary health issue I have a weight lifting restriction but I guess I could get a helper or two just for the heavy part. Right now I have to find the time to troubleshoot the electrical part.

I am a little concerned with replacing the cooling unit. I have read several reviews where people had to do a lot of forcing and broke the plastic in the inside of the box where the cooling fins come through. Few others report it is an easy job. However, there wasn't much detail in the reviews. I am perfectly capable of replacing the cooling unit "IF" the new unit fits properly. Removing the old fridge and installing a new one is an easy job just more expensive. decisions, decisions.

I appreciate the responses here but would love to hear from somebody who has replaced a cooling unit. I'll keep checking back and will post my final outcome.

 

[Gary RV_Wizard]

Sounds like an absorption fridge is your best choice so you can stick with propane power.


I've not ever disassembled a Dometic but Norcolds are easy. In both cases, the cooling unit simply bolts on the back, but has a thermal sealing compound that may require a bit of prying to get loose.  Just work slowly and it should come out ok. The toughest part is all the wiring on the back side, carefully labeling (and take photos!) and disconnecting and working around the tangle. More nuisance than technically challenging.

 

[John From Detroit]

When I had the cooling unit replaced I had My RVGIRL do the job
(That's her service truck's license plate by the way)

She is a professional and did a very good job.. I assisted but mostly with "Grunt" work  She did the actual work

Total problems encountered.. ZERO  but then she has done this before and knows what she is doing.. I on the other hand... do not. .Which is why I sought professional help .

Now if I had to do it again.. not sure if I'd hire her or not. but I won't be doing it again.

 

[RVfixer]

Well, here is where I'm am so far. Can't find a new fridge in stock and no delivery dates. I have decided to replace the cooling unit and have resolved the electrical issue. Come to find out, and I should have known, when the cooling unit goes out the boiler section in the stack overheats. The thermal fuse is on the outside of the stack (above the burner and behind the recall wall). I pressed the button on the thermal fuse and the front panel and door light work again. I let the fridge run on electric and in a few minutes the fuse tripped again and I got more ammonia smell. The ammonia smell was so light at camp that I wasn't real sure of my diagnosis. This more than confirmed that the cooling unit is shot.

I removed the 4, screws top and bottom, at the front of the fridge, and the two in the back from the outside. I was ready to disconnect the power wires and propane line when the rains came. I plan the pull the fridge and separate the cooling unit from the fridge before ordering the new cooling unit. I think I am going to go for the new, not reconditioned, Amish cooling unit. My fridge is a DM2652RBX...the RBX means the cooling unit was made in Japan or Germany for but not by Dometic, It does not have a frame around it. Two places I checked for cooling units give a $100 rebate if you send back the old cooling unit on them...but NOT for the RBX cooling unit. My bad luck is holding.............. Film at Eleven........

 

[kennyshark]

I just checked in late and had the same problem, minus the ammonia smell, I replaced the thermal switch after resetting it and had the same problem. No 12 volt, I've decided to pull it and replace it with a Frigidaire 10.1 cu ft. of course I had to order it as no one has one in stock, but they are much more efficient to run than the gas/electric one. I have a 1000 watt inverter and two 6 volt golf cart batteries to run it when I'm not plugged in. 

 

[RVfixer]

I thought I would report back and update this thread.

Short Review: My fridge quit...lights out on eyebrow panel and ammonia smell. No fridges were available unless you wanted to buy one with an RV wrapped around it. I hesitated ordering a new cooling unit until I resolved the electrical problem. The reason for no lights and no attempt at cooling was the that thermal fuse had popped due to overheating caused by the cooling unit failure.

I ordered a new build Amish cooling unit from David Force at The RV cooling Unit Warehouse online. During the job I emailed David a couple of times and he replied within minutes each time. The shipping was fast, the CU arrived in perfect condition. I worked the job by myself so I had to work out some interesting workarounds on working alone to get the fridge out, the new cooling unit in place in the fridge box and the fridge reinstalled. I took my time and was happy with the results.

I have read a few posts and heard from a few RVers where they were not happy with the cooling after a cooling unit replacement. There are two main items that can cause this....Not properly sealing in the foam block containing the cooling tube and not getting the cooling tube up against the metal freezer plate. Some of the cooling unit sites say not to use the canned insulation foam to seal the unit in...Instead they recommend using weather stripping. Luckily I read my warranty paperwork before starting the job. On the Amish cooling unity warranty it says, "Failure to use the provided foam to seal in the CU foam block voids the warranty."

The instructions say to make sure you get the cooling tube in the foam block hard against the metal plate back freezer wall. It doesn't tell you how to do that. Then it says that due to the variances in the fridge boxes the foam block may not go down flush, it may stick up a little after installation and that is OK. Mine did stick up a little. When you put the CU on the back of the fridge the foam block goes into a recess on the back of the fridge....So, how do you know if the foam block is all the way down (especially when it sticks up a little) and how do you know that the cooling tube inside is against the freezer metal plate?? In my opinion this step and sealing in the foam block are the most important steps for success and good cooling.

I thought of a few ideas to be sure the foam block was all the way down and the zigzag cooling tube in that foam block was against the freezer plate. The one I used was chalk on the cooling tube. I did a dry (no thermal mastic and no foam sealant) fit check after trimming down some foam block high spots,  When I removed the cooling unit I had a zigzag line of chalk down the freezer plate. Works for me!

For my final installation I put the bead of thermal mastic on the cooling tube and two rows of foam insulation beads on the recess walls in the fridge box and installed the CU into the fridge box. To get the fridge back in it's cabinet I reversed the process that I used to remove it. I used a little roller that I move my generator around on at home and stacked two rows of short boards on the roller up to the level of the bottom of the fridge. I slide the fridge out of it's cabinet onto the boards, rolled it to where I wanted to work it in the trailer and tilted the fridge back and forth, taking one board out at a time and walked the fridge down. I walked it back up on the roller and reinstalled the fridge in the same manner. Job complete. The following was my start up test: (After doing all this work you have to play with it...Right?)


Outside temp.  = 10:30 AM  68 degrees F.  Today's high to be 72 

Starting temp:  Inside fridge box  =  60    ..........Inside freezer  =  60 

After one hour....  Fridge =  58      Freezer =  32

After two hours                    45                        15

After three hours                  35                        +5

After four hours                    33                        +2

After five hours                    33                        +2

I let it go for 2 more hours without opening the doors and got the following

After seven hours                33                          0 degrees

** Notes:

* Fridge and freezer were empty
* I opened the doors every hour
* It is a cool, no sun day
*** Works for me!

 

[Gary RV_Wizard]

Thanks for the feedback and congrats on a job well-done!

I think many of the complaints about poor fridge performance are due to sloppy installation procedure, whether DIY like this or factory installs.

 

[CharlesinGA]

I thought I would report back and update this thread.

Short Review: My fridge quit...lights out on eyebrow panel and ammonia smell. No fridges were available unless you wanted to buy one with an RV wrapped around it. I hesitated ordering a new cooling unit until I resolved the electrical problem. The reason for no lights and no attempt at cooling was the that thermal fuse had popped due to overheating caused by the cooling unit failure.

I ordered a new build Amish cooling unit from David Force at The RV cooling Unit Warehouse online. During the job I emailed David a couple of times and he replied within minutes each time. The shipping was fast, the CU arrived in perfect condition. I worked the job by myself so I had to work out some interesting workarounds on working alone to get the fridge out, the new cooling unit in place in the fridge box and the fridge reinstalled. I took my time and was happy with the results.

I have read a few posts and heard from a few RVers where they were not happy with the cooling after a cooling unit replacement. There are two main items that can cause this....Not properly sealing in the foam block containing the cooling tube and not getting the cooling tube up against the metal freezer plate. Some of the cooling unit sites say not to use the canned insulation foam to seal the unit in...Instead they recommend using weather stripping. Luckily I read my warranty paperwork before starting the job. On the Amish cooling unity warranty it says, "Failure to use the provided foam to seal in the CU foam block voids the warranty."

The instructions say to make sure you get the cooling tube in the foam block hard against the metal plate back freezer wall. It doesn't tell you how to do that. Then it says that due to the variances in the fridge boxes the foam block may not go down flush, it may stick up a little after installation and that is OK. Mine did stick up a little. When you put the CU on the back of the fridge the foam block goes into a recess on the back of the fridge....So, how do you know if the foam block is all the way down (especially when it sticks up a little) and how do you know that the cooling tube inside is against the freezer metal plate?? In my opinion this step and sealing in the foam block are the most important steps for success and good cooling.

I thought of a few ideas to be sure the foam block was all the way down and the zigzag cooling tube in that foam block was against the freezer plate. The one I used was chalk on the cooling tube. I did a dry (no thermal mastic and no foam sealant) fit check after trimming down some foam block high spots,  When I removed the cooling unit I had a zigzag line of chalk down the freezer plate. Works for me!

For my final installation I put the bead of thermal mastic on the cooling tube and two rows of foam insulation beads on the recess walls in the fridge box and installed the CU into the fridge box. To get the fridge back in it's cabinet I reversed the process that I used to remove it. I used a little roller that I move my generator around on at home and stacked two rows of short boards on the roller up to the level of the bottom of the fridge. I slide the fridge out of it's cabinet onto the boards, rolled it to where I wanted to work it in the trailer and tilted the fridge back and forth, taking one board out at a time and walked the fridge down. I walked it back up on the roller and reinstalled the fridge in the same manner. Job complete. The following was my start up test: (After doing all this work you have to play with it...Right?)


Outside temp.  = 10:30 AM  68 degrees F.  Today's high to be 72 

Starting temp:  Inside fridge box  =  60    ..........Inside freezer  =  60 

After one hour....  Fridge =  58      Freezer =  32

After two hours                    45                        15

After three hours                  35                        +5

After four hours                    33                        +2

After five hours                    33                        +2

I let it go for 2 more hours without opening the doors and got the following

After seven hours                33                          0 degrees

** Notes:

* Fridge and freezer were empty
* I opened the doors every hour
* It is a cool, no sun day
*** Works for me!

Thanks for the excellent write up. Replacing the cooling unit is probably the best way to go, the fridge fits in the opening, no remaking the opening for a different fridge, it certainly didn't cost as much as a new fridge, which you could not even get, and it works GOOD now that it is done. WAY TO GO!!! Glad to see people actually fixing stuff themselves and doing it correctly.

If I'd done the fit test I would never have thought of chalk, I would have use (very messy) Prussian Blue, because that is what I have. Excellent info, I may have to do this someday, I have an RM2662RB according to the trailer mfg spec sheet I have a pic of, will have to look again at the model numbers on the fridge itself.

DID YOU USE BLUE CHALK DUST LIKE YOU USE ON A STRING TO SNAP A CHALK LINE?

Charles

 

[RVfixer]

CharlesinGA

You asked if I used string chalk. No, I had thought of several choices to get a transfer trace from the side of the zigzag coolant tube onto the freezer plate and most seemed messy. I decided to try chalk. Any chalk would do and I was going to run up to the store and get some blackboard chalk which I am sure would have worked fine. My wife does a lot of sewing as a hobby and she suggested and volunteered her blue tailors chalk. That chalk is a tad oily and doesn't drop powder...Worked great!

Because I was working with no helper I had to do some workarounds. The instructions call for putting the mastic paste on the side of the zigzag cooling tube on the back of the foam block. The mastic is in a tube that requires a sealant gun. It is a non hardening paste that is full of aluminum powder and aids in transferring the cooling from the tube to the freezer plate to the refrigerator section cooling fin assemble. You then install the cooling fin assembly onto the lower section of the cooling tube over the mastic in that area. The top portion of the cooling line, with a mastic bead on it goes against the freezer plate when the cooling unit is installed into the fridge box. Per the instructions you put two rows of the spray foam around the side walls of the recess in the freezer box where the foam block with the mastic coated cooling line and fridge fins fits into. The fins fit through a cutout in the thin plastic liner of the fridge section. Then the instructions call for holding the cooling unit parallel to the ground and lower it into the fridge box which is laying on it's face. Try doing that by yourself. I decided that was not going to work for me.

What I did I think I would do again even if I had a helper. The instructions call for you to lower the cooling unit into the fridge that is laying on it face. Most people crack the plastic lining in the fridge where the cooling fins passes through into the fridge section.  That is not a problem but I'd rather not crack that plastic liner. Then the instructions call for building up the removals...power module, brackets, gas valve, burner box with probe, etc., route and hook up all the wiring, etc. I guess if you are doing this for a living and have done many...and have a helper that would work...However, the foam seal is curing as you do all that and you have not installed the freezer plate screws and pulled the cooling tube up against the plate yet. Below is what I did and would do again even if I had a helper.

I stood the freezer box upright. With the mastic and fin assemble installed on the cooling unit I could easily lift the cooling unit in the upright position and move it over to the fridge box. In this configuration I could look over the top of the foam block and line it and the fins up to enter the recess in fridge box. If the fins are a little high to pass through the tight cut out in the box just move the bottom of the cooling unit back a little, if the fins were low move the bottom of the cooling unit forward a little. When lined up well push it in...no cracking of the plastic liner or smearing of the foam seal due to having a good view over the foam block and full control due to a one person operation and not fighting each other. The other benefit of installing the cooling unit with the fridge box upright is that after you put the corner frame screws through the cooling unit frame and into the fridge box you can then install the screws through the freezer compartment and pull the cooling tube hard against the freezer plate before the foam cures and hardens.

Another tip: The cooling fins for the fridge section install over the mastic on the lower part of the cooling unit foam block with four screws. There is a lot of slop in those screw holes in the fin assemble. Because the fin assembly fits through a tight cutout in the thin plastic liner...I left the four fin mount screws just lightly snug. This allowed the fins to move a little and line themselves up while passing through the close fit cut out. After installing the freezer screws I put the final torque on the fin assemble screws inside and at the top of the fridge section. THEN, you can lay the fridge down on it's face and take all the time you want to reinstall all the removed items and route and hook up the wiring.

Another important part of this job, per the instructions: At the top of the cooling unit there is a set of cooling fins with a couple of tubes passing through. This is the condenser and is just a couple of inches below the top of the fridge box with the cooling unit installed. The instructions call for making sure that this condenser is level with the top of the fridge box. The frame and tubing of the cooling unit will move a little independent of the sealed-in foam block. The holes in the corners of the cooling unit frame are large clearance holes. It is easy to loosen those top frame screws and push the fame a little to level the condenser with the top of the fridge box. After doing that, and tightening the screws in the frame clearance holes. I drilled a couple of new non clearance holes through the frame and into the fridge box to install tight fit screws and make sure the frame didn't move in the clearance holes during rough travel. Because I read all the instructions before starting the job I was able to check the old condenser levelness once I got the refrigerator removed. It was pretty much off level. I guess you could say that, even though I an kind of fanatical about getting my trailer level for proper operation of the fridge...you could say the fridge has been running off level for over 9 years due too a sloppy factory install of the cooling unit!

I had fun with this project and fun writing these posts.