Dometic RMD 8555 runs cooler now

[Patandlinda]

Originally Posted by Santiago

Pat, I don't have a propane fridge but I have the same (dimensionally speaking) 21ft standard fridge cabinet and can share my observations. My 2016 21ft fridge cutout dimensions are identical to other 21ft trailers. Only difference being that my back wall is solid, no wall vent cutout. The sides, top and bottom are the same as the standard 21ft fridge cabinet.

I removed the luan pieces glued to the both left and right sides of the cabinet. I did not order the left wall reinforced. Reason was to expose the 1x3/4" framing. Those were filled with 3/4" Rmax Thermasheath Polyisocyanurate Rigid Foam Insulation Board.
On the right side, 1-1/2" boards topped it off preventing framing thermal "bridging", making 2-1/4" thick total insulation. On the left side the topping was 2" minimum for total of 2-3/4" thickness. On the bottom below the plywood shelf, 2" board wall to wall. On top 3". The back I started with 2" and reduce to 1" OVER the factory bubble wrap insulation, ( this does not apply to the propane units). My fridge has same width as the Dometic one and slid right in.

So, if you are willing to remove the unit, get rid of the luan, you should be able to add a lot of "R"s. This does not apply to the back since you have vent door back there. If you are interested, I can submit a few photos.

Hi Santiago . If you have pictures always willing to learn . We only have the 4.3 . Since we always will bring a cooler it is plenty for us . I'd have to dig out my old pictures but they probably on the long thread of all of us fixing our refrigerators .there are a few in our albums on the forum . There was a space on both sides of our refrigerator I installed I think it was 2 in solid foam product . I installed also a piece on top . Sealed off the front . Basically made a sealed cabinet . Sealed up the back too. I installed a waterproof fan inside the fridge , I can operate . I installed a on and off for the fan that was on the back of the refrigerator that never came on , I can operate . And installed the ventilator fan with a on and off . I can operate all these fans from inside if needed . Letting the thermistor hang inside . I don't know Santiago but we have been getting very good temps on 4 even in heat over 100. 31 in morning , going up to 38 . Might go to 43 if we open door but it recovers in a couple of hours . Temps are even much better if weather is cooler . I even make ice cubes in the freezer . Frozen food stays frozen . I did some other things to cavity back there . Oh I pulled the the little baffle and redid it to make it 45 degrees as another member suggested to do ,added more reflex to outside wall . Santiago any pictures if you have , maybe can help others too. The performance is now like We were used to on a the older Dometic's just no blue led's . Pat

[Santiago]

Donna, following up on how I insulated my 2016 classic 21 standard fridge cabinet.

1. 2" iso board on bottom. Slot on rear is for cool air originating at grill on left side of furnace cabinet to rise past electric fridge heat rear heat exchanger.
Note luan is gone exposing 1-1/2 x 3/4 framing. on walls

2. Wall framing filled with 3/4" iso boards.

3. Factory 3/4" ply shelf back on with slot for cooling air. One 6vdc 6CT AGM battery housed underneath fridge.

4. Start of rear wall insulation over factory bubble wrap insulation. Starts with 2" iso board, graduates to 1", 3/4" then only bubble wrap due to curvature of wall AND electric fridge heat exchanger assembly (like the fridge you have at home).

[Santiago]

5. View of where the bottom 2" iso board goes. Should be directly under fridge but a solid floor ( 3/4" ply ) is a good idea. Note the oak structural member across used to reinforce battery from side movement.

6. ( VIEWING SIDEWAYS ) Mounted fridge showing mild steel angle iron supporting battery from lateral movement in other direction. Strap across keeps battery from vertical movement. Design allows changing battery out without bothering fridge.

7. Rear 2" back wall insulation sculpted to direct cooling air flow.

8. ( VIEWING SIDEWAYS ) Second layer of iso boards added. Note 400 mm exhaust fan upper left. 0.15 amp, quieter than a church mouse, really! It is housed on fridge attic isolated from lower section. One more layer to add.

[Santiago]

9. 2" iso ceiling that isolates fridge section from attic. Foam sculpted and covered with ML-181 aluminized duct tape to aid air flowing to attic from back of fridge heat exchanger section. Above attic is 1" iso, had room might as well.

10. View from fan opening into attic. Note back air flow entry cutout directing heated air flow from heat exchangers below to attic on way to fan.

11. ( VIEWING SIDEWAYS ) Completed cabinet insulation projecy with 12 vdc power lines waiting to be plugged in to electric fridge. No other power source required and Noval Kool stated the fridge will operate at a 45 degree angle.

12. Upper back wall showing warm air entry way to attic then fan. Heated air naturally flows up (convection) but added quiet fan to make sure it does.

[Santiago]

One last item. The Dometic that would have been installed by ETI is like 2 inches taller. However since your fridge will not have an attic you will likely have as much or more room on top. The horizontal cabinet opening is nearly identical and the bottom resting plywood shelf the same.

[Patandlinda]

Originally Posted by Santiago

One last item. The Dometic that would have been installed by ETI is like 2 inches taller. However since your fridge will not have an attic you will likely have as much or more room on top. The horizontal cabinet opening is nearly identical and the bottom resting plywood shelf the same.

Santiago found some pictures . Pat

[Patandlinda]

Originally Posted by Patandlinda

Santiago found some pictures . Pat

more pictures

[Patandlinda]

Originally Posted by Patandlinda

more pictures

and finally inside fan , controlled by switch in closet. thermistor just hangs now out of holder for about 2 years. Pat

[Santiago]

Very nice work as usual Pat.

This is first time I've seen a working Escape 19 propane fridge cabinet in the inside. Bottom line as per your good experience, there seems to be room to add insulating boards. From member reports here, insulation helps their propane fridge's performance. Seems like it did for you too.

Insulation is like money and sex, you can't have too much of it.

[Patandlinda]

Originally Posted by Santiago

Very nice work as usual Pat.

This is first time I've seen a working Escape 19 propane fridge cabinet in the inside. Bottom line as per your good experience, there seems to be room to add insulating boards. From member reports here, insulation helps their propane fridge's performance. Seems like it did for you too.

Insulation is like money and sex, you can't have too much of it.

Thankyou .Yes ,never use the 12 volt . Use gas traveling and when boondocking. 120 to start at home and if we get hookups . Even in the older Dometic's found the gas worked the best and fastest . Still rings true . Santiago behave yourself ! Pat

[LeonW]

Originally Posted by nathanj04011

I was told by Sarah in 2016 before we picked ours up that they had started putting in pink insulation around and behind the fridge after a few members here had done it with some success. Seemed to work when we first got the trailer in June 2016; our RM8xx got pretty cool, in the 30's for the fridge and the single digits for the freezer. This year, on setting 5, it can only manage the low 40's and upper teens for the freezer.

I talked to my RV Tech about pulling the fridge and adding insulation around it, but he said it had already been done. We had ETI swap the fridge out in May of 2015, just after the rally. I assume they added the insulation then.

The fridge does "OK", especially after we removed the thermister from the fins.

[PGDriver]

Having dealt with absorption fridges now for 30 plus years these are a few things I've noticed. Thought I would just put this out there and maybe it will help someone.

1. Best to cool down fridge a day or two before packing and moving.

2. Best not to ever have a thermistor touching the cooling unit or side wall, dangling is best.

3. Every couple of years clean out the burner tube/chimney you'll be surprised what falls out.

4. Don't over pack fridge.

5. Always have a little Camco or other type of fan inside, lowest shelf at the back corner away from dangling thermistor is best.

6. When you buy more groceries, expect the fridge to take awhile to recover.

In general I think that people expect to much out of an absorption fridge unit. The process is not the same as a compressor unit nor are the abilities.


Cheers
Doug

[m&k]

Thanks, informative post.

[thoer]

Good list Doug.

One thing I would add is to keep extra freezer space full of blue ice or ice of any kind. The more frozen things we have in our freezer, the more it seems to mitigate temperature swings. We use blue ice and when we put warm stuff in the fridge from a shopping trip, moving one or more of the blue ice's to the fridge seems to help it not warm up nearly as fast. Then later we move the blue ice back to the freezer.