Roadtrek 210P Refrigerator Problem Solutions

[peteco]

The Dometic RM2554 refrigerator in my 2006 Roadtrek 210P had poor performance in hot weather with fridge temperatures into the mid 40’s in hot weather. The fridge was slow to recover after opening the door more than just a few seconds. The freezer was good at near 0-degrees. Note that some of these issues could be somewhat different for vehicles other than the RT 210P. But the same principles apply.

The Dometic installation and service manuals showed that the vent area behind the fridge needs to be configured properly to get adequate venting. Roadtrek did not install the proper vent cavity setup, and there is too much gap, which causes poor airflow over the absorber and condenser coils. I installed an inner wall to eliminate the large gap between the van sidewall and the fridge coil system. The wall should extend up close to the upper coil. I also made an airflow deflector to help direct the air out the top vent. Dometic shows a deflector above the condenser but doesn’t say anything about it.

I put foam insulation between the Van wall and this new inner wall to reduce solar heating of the outside wall from heating the vent cavity. I also stuffed insulation above and on the sides of the refrigerator.

I installed three small low-amperage computer fans in the upper vent to pull air through the vent cavity and out the vent. The fans coupled with the proper vent cavity geometry has the biggest effect on cooling improvement I believe.

A small blue battery fan circulates air inside the fridge. I may install some 12-volt fans blowing over the evaporator fins as others have said that works well.

I had to replace the refrigerator a few years ago as it had become insufficient keeping the fridge at a safe temperature. When I removed the old fridge I found the 120 and 12v heating elements rusted tight in their housing. The 210 design allows rainwater to easily enter the upper fridge vent due to the sidewall slope. I installed a water diverter on top of the insulated heating section to direct water off. I also made wall plates that replace the sidewall vents when I am not going to use the fridge for a long time (like a few weeks or longer). This is to keep all rainwater out. I have made a big placard that goes on the fridge door to remind me to remove the outside wall plates when I am going to use the fridge.

Since the upper vent is on a slope, the 3 vent opening bottoms can collect rainwater. I thought this would be a problem while driving as that collected water can get blown back up into the refrigerator. I filled the bottom ”cup” of each vent with flowable epoxy coating system material so water could not collect there. I put silver vinyl wrap material on top of the cured epoxy to protect it from the solar UV.

https://www.amazon.com/Environmental-Technology-8-Ounce-Pour-Finish/dp/B001CEMU3I/ref=asc_df_B001CEMU3I?mcid=bb606c6ae62f3f859b4c228eb437c90f&hvocijid=15662953464808196858-B001CEMU3I-&hvexpln=73&tag=hyprod-20&linkCode=df0&hvadid=721245378154&hvpos=&hvnetw=g&hvrand=15662953464808196858&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9189467&hvtargid=pla-2281435178618&psc=1

I also had installed an ARPRV unit many years ago to protect the fridge from off-level overheating. These units have gotten more expensive (like everything), but I think it is a good protective device. When parked off-level for a while one should turn the fridge off. The ARPRV unit will protect the fridge if I forget.

Fridge Defend | ARP Control | RV Safety | Dometic | Norcold | RV Fire

Your RV Refrigerator boiler operates at about 350 degrees all the time, but even a brief time off-level, like driving up a hill, can send that temperature sky-rocketing. Events like this produced a lot of thermal stress in the fridge boiler, stress that causes the metal to fatigue and the...

www.arprv.com

I try to not put hot foods or a lot of room temperature items in at one time.

With all these mods and close monitoring I am happy with the performance of the fridge.

This Dometic RM2554 has been discontinued. If this refrigerator fails I will likely install a compressor unit, though that would also require extensive cabinet, battery and electrical system upgrades.

Original Posting in 2018. Many changes have been made since then.

Gas Absorption Refrigerator Mods to Improve Performance

 

[GallenH]

Nice writeup and pics. Thanks

 

[peteco]

Forgot to mention. youngnretired great fridge fan posting prompted me to update my fridge information.

2008 Chevy Roadtrek 210 Popular Refrigerator Exterior Cooling Fan Install

My wife and I bought our first "modern" camper in April 2025. We've owned an older popup camper for a couple years now, but never owned anything like this that's all self contained. We bought a 2008 Chevy based Roadtrek 210 Popular. The RT came with a newer replaced refrigerator and when that...

www.classbforum.com

 

[booster]

Pete's changes are the poster child for how the passive, or fan boosted, airflow needs to be handled on the RV frigs to get decent cooling and efficiency. Having the most vertical and small crossection air path gives the most airflow over what is needed to be cooled.

This is true for both the absorption and compressor frigs although they all are slightly different in how you need to do it. The absorption and compressor frigs with old school "S" coils on the rear need wide narrow ducts similar to Pete's but the compressor/condenser modular units like our Isotherm use just a sealed duct from the fresh air inlet to modular unit fan.

 

[youngnretired]

Peteco, do you have pictures of what your internal baffling box that you made and installed that you could post, or is this more difficult because it's installed, and how did you attach it inside the cavity so it wouldn't just flop around?

When water gets inside this cavity, does it exit or where does it go?

 

[peteco]

Peteco, do you have pictures of what your internal baffling box that you made and installed that you could post, or is this more difficult because it's installed, and how did you attach it inside the cavity so it wouldn't just flop around?

When water gets inside this cavity, does it exit or where does it go?

There are drain holes in the bottom floor under the fridge. Check them to make sure they are not clogged.

I will get pictures and provide a writeup, but may take a few days.

 

[peteco]

Roadtrek 210P Refrigerator Problem Solutions (part 2)

Here are additional details regarding the vent mods.

Picture 1: Upper vent opening. Curved baffle at top to direct hot air toward vent openings and fans. Baffle is screwed to cabinet wall and sealed with aluminum tape. Next down is white plastic or nylon sheet (3/16 to ¼ inch) that directs vent air through the condenser coils. The sheet is attached at their upper right and left corners to the vent frame with a ¼-20 bolt. The frame has 7 holes that are tapped to a ¼-20 thread. These 7 holes also accept the seven ¼-20 solid vent cover attachment bolts. There is sufficient depth to these two side holes to hold both the plastic sheet shown here and the vent cover screws; adjust the screw length accordingly to fit both.

Picture 2 & 3 is view of left and right sides. White plastic sheet is attached to aluminum baffle box wall made from aluminum RV siding scrap pieces I had. The aluminum baffle box wall is attached to the cabinet enclosure sidewall with angle aluminum. This was the hardest item to install. It would have been better if I had unscrewed the refrigerator and moved it inward to provide more room to work. At the bottom of the vent frame is a piece of thin plexiglass that is caulked to the frame to prevent water from flowing into the vent cavity. Water that leaks through the vents and vent cover edges can flow into the vent cavity because the van side wall is angled inward a little bit, instead of vertical like it would be on a typical flat wall camper.

Picture 4 is a view down into the cavity showing the gap between the inner box baffle wall (which is within about ¼-inch from the refrigerator absorber tubes) and the van sidewall. The large gap between the van sidewall and the absorber tubes & condensor is what causes poor vent airflow on the original installl. The baffle box increases the airflow around the coils to provide better heat transfer out of the refrigerator. It would have been nice if Roadtrek had installed per Dometic instructions.

Picture 5 view is upward from the lower vent opening. A curved sheet metal transition attaches to the baffle box wall aluminum sheet mentioned previously. The boiler tube enclosure has aluminum sealing tape on it to prevent water from entering and causing rust.

Picture 6 shows the lower vent opening. A water dam is at the bottom of the frame to prevent water entry at that point, similar to the one installed at the bottom of the upper vent. Plastic water protection covers have been placed over key items: ARPRV control unit (left wall), electric junction box, gas valve.

Picture 7. While taking these pictures I realized solar heating could perhaps be reduced by installing reflectix on the wall of the baffle box. The reflectix was installed in 3 pieces. Then a pool noodle was cut in half and pushed down the cavity to hold the reflectix on the baffle box wall. A gap is needed between the van sidewall and the reflectix for the radiant heat to be reflected back outward.

Pictures 8, 9, 10. Some details on the solid vent covers. Made from King Starboard purchased from Home Depot. This board can not be painted. Vinyl wrap does not stick either. I already had some silver vinyl wrap that matched the color exactly. So the vinyl wrap is held with thin aluminum strips screwed to the back of the Starboard. It would be easier to find a vent cover material that the wrap would stick to but I already had the Starboard. The cover attachment screws are ¼-20 phillips head. I ground the threads off near the head so the screws float in the Starboard. A thin plastic washer protects the vinyl wrap, though it has puckered a little bit where the washer contacts the wrap.

Lots of OCD content here, and these have evolved over the 14 years I have had the Roadtrek. I wanted to do everything possible to vent the refrigerator cavity, protect the fridge from off-level overheat (hence the APRV unit), and to prevent rainwater entry or damage as much as possible. I believe each mod provided an incremental improvement and overall the refrigerator works well now.

 

[booster]

Great pix and writeup Pete.

Certainly looks like it is very much optimized at this point. With the better ventilation and performance to you find the frig more tolerant of being out of level if it does happen on occasion?

Looking at the pix, it appears that Roadtrek has a plywood floor in that area? If so, that much be a 210 thing as our 190 is the metal van floor in the frig area. Our floor also has a large opening with steel mesh on it that goes gives an air vent to the underbody which I don't know is good or bad because when you drive the underbody in a negative pressure area AFAIK and could disrupt the upward air travel of cooling air.

The plywood floor if it is that way would certainly indicate a need to keep the water out of there, but I don't see any water staining that is obvious. The lip on the bottom of the opening should really help that. It makes me wonder if there is a full fiberglass floor that fills the widened area back to original van floor to keep out water.

The rusting of the absorption frigs tubing has always been of interest to me, especially when the rust is in areas that are not all that likely to get rain water in.

Living in the area we do with cold winters I see underbody, underhood areas get rusty from just sitting outside, while indoor storage vehicles stay rust free in those area. This comparison is looking only at non salt driven vehicles though as salt driven ones always rust all over. I think here and probably in areas with cool nights and humid air in warm areas what is going on is the steel getting cold overnight and then the humidity goes up in the morning and you get condensation on areas that are hidden, but air gets to. Rotor rusting is probably the one we see most as well as parking brake cables that rust and stick.

As similar process as above may happen on the frig parts also as it is pretty common, I think, in humid areas to condensation over the entire body in morning.

 

[peteco]

Certainly looks like it is very much optimized at this point. With the better ventilation and performance to you find the frig more tolerant of being out of level if it does happen on occasion?

Looking at the pix, it appears that Roadtrek has a plywood floor in that area? If so, that much be a 210 thing as our 190 is the metal van floor in the frig area. Our floor also has a large opening with steel mesh on it that goes gives an air vent to the underbody which I don't know is good or bad because when you drive the underbody in a negative pressure area AFAIK and could disrupt the upward air travel of cooling air.

The plywood floor if it is that way would certainly indicate a need to keep the water out of there, but I don't see any water staining that is obvious. The lip on the bottom of the opening should really help that. It makes me wonder if there is a full fiberglass floor that fills the widened area back to original van floor to keep out water.

The rusting of the absorption frigs tubing has always been of interest to me, especially when the rust is in areas that are not all that likely to get rain water in.

I can't tell any difference in out of level performance, though these mods have been implemented one at a time over many years.

I think the floor under the fridge is probably fiberglass, There are 2-3 channels that slope down toward the center of the van with a drain hole at the end of each channel.

 

[youngnretired]

Thanks for the writeup on this. I wanted to create something like this for our trip last fall, but ran out of time before we left. However, I did "rig" up something a little different. I was trying to figure out how to create a barrier so that air would only flow thru the coil area only, and not between the coils and exterior wall of our 08C210P, and do it pretty quickly. I had some 4" batt insulation and thought this would be excellent to put in behind the refrigerator. So I cut a section of the 16" wide batt insulation so that when installed sideways would fill up the entire width of the refrigerator service and cooling area. It took a bit to get the batt in there and I just used some zip ties to hold it up thru some holes I cut thru the batt insulation. I was going to use PEX tubing thru the holes in the batt insulation, but didn't end up using them as I thought the batt insulation would hold up and not have the zip ties tear thru the insulation. It worked, and I think it worked very well. It actually created some insulation barrier to minimize heating up the area from the sun.

As previously commented elsewhere on this forum, I had previously added two additional fans to the upper access panel for refrigerator cooling to compliment the one fan that was installed by the PO when the refrigerator was replaced. Before leaving on our trip, I unwired one of the fans leaving two wired and installed a second temperature switch. I wired the fan closest to the burner heat riser tube to operate on the lower temp switch (on at 104F and off at 87F - yes I know that under certain conditions this fan may never shut off) and the fan in the middle of the upper access panel to operate on the higher temp switch (on/off at 130F). I used the Wago lever style electrical connectors, so at any time I could wire or unwire fans as needed on the trip without requiring much effort. I will say that the fridge stayed pretty much in the mid to upper 30's 90-95% of the time, and I even lowered the cooling requirement setting typically by one setting. At night while laying in bed, by listening to the fans, you could hear where it was in a heatup or cooldown cycle by the different fans coming on and off. Overall, I would say that this worked well for our trip. Sorry, no installed pics as there's not much to show except for batt insulation between the coil and exterior of the camper shell.

 

[booster]

I think the batt insulation is the best way to plug the area because it is easy, removable, insulates, and is fire resistant. It is what I have used since day one.