Dometic RM-77 Replacement

[Erik Olson]

My original two-way (110V/LP) Dometic RM-77 packed it in at the end of last season - mmm... ammonia! - and I'm going to try and install the new unit myself.

My current unit is an RM-77, left-hinged set-up, tucked very neatly (read: tightly) into the original, unmodified 1974 Ambassador mid-twin model, single pantry layout cabinetry. In this set-up, there is a long shelf-bin atop the refrigerator and pantry.

Dometic recommends the RM2820 as the replacement for the RM-77. When I look at the specifications, the recess dimensions look great. My concern is the overall dimensions required for the 2820 unit.

RM-77 (BUILT-IN SPACE REQUIRED)
56-7/8"H | 23-13/16"W | 23-5/8"D
RM-77 (CABINET OVER ALL DIMENSIONS)
56-1/2"H | 23-7/16"W | 24-5/8"D

RM2820 (RECESS DIMENSIONS)
55-7/16"H | 23-11/16"W | 24-3/32"D
RM2820 (OVERALL DIMENSIONS)
57-7/8"H | 24-39/64"W | 24-9/16"D

http://www.dometic.com/c17faeab-a5a2...17a7cff0.fodoc

Has anyone upfitted their refrigerator in this model? I'm really agonizing over the difference in dims and wonder if I'm going to have to severely alter my cabinets to accommodate the new refer.

Thanks in advance for any advice you might have.

[Aage]

Well, if your RM77 isn't in rough cosmetic condition, another alternative is to replace the 'innards', if you don't want to worry about size (or price). This company is one of a few that rebuild the cooling unit in your refer, at something like less than half the cost of buying a new one. RV Cooling Unit Warehouse

But if it's rough, forget this idea. Who wants a refer that won't clean up? No wife I know...

[Erik Olson]

I ordered a Dometic 2820R model refrigerator with left-hand option.

We have it about halfway installed now, and managed to get the electric control panel, which sits at the top of the new unit, under the stock shelf that is over the pantry and the refrigerator position.

I added a 1.5" , 1.5" x 5' firring strip on the back of the bulkhead wall to tie into the refrigerator. The OEM refrigerator was physically screwed into the bulkhead and pantry. There will be less points contacting these areas moving forward, however, I plan to stainless lag the 2820 into the floor from the outside access port. On the original unit, there is no sign that this was ever done?

I've taken a lot of time to make sure that this will be a very clean installation that surpasses what was done on the original build.

I will take some pictures tomorrow and post them up.

Thanks!

[LeeJ]

I am replacing the original Dometic in my 85 sovereign. Any recommendations for frequency of running the refer periodically while it's in storage? I want to avoid the clogging and corrosion for as long as possible, like another 29 years.
Thanks for your recommendations
Lee

[Protagonist]

Originally Posted by LeeJ

I am replacing the original Dometic in my 85 sovereign. Any recommendations for frequency of running the refer periodically while it's in storage? I want to avoid the clogging and corrosion for as long as possible, like another 29 years.
Thanks for your recommendations

My opinion is, it makes no difference. The important thing isn't how often you run it, but how clean it is. Especially on the back side where the combustion occurs. Clean the vent when you put it away, and before you use it again. Clean the burner when you put it away. Remove any carbon build-up from the sensor. Once clean, the burner and sensor should stay clean until you use it again, aside from possible nesting spiders and such, so check it again before you fire it up for the next trip, and clean it again if necessary.

Store it with the door propped open so any condensation will evaporate out of it, and clean it thoroughly inside to prevent mold. Every so often (each time you store it) do the "dollar bill" test on the seals; close the door on a dollar bill, then try to pull out the dollar bill without opening the door. If it comes out easily, time to replace the seals.

If it doesn't have a refrigerator exhaust fan, add one. Heat buildup around the coils is a major life-shortener for the fridge since it makes the fridge work harder; ensuring that heat is carried to the outdoors will do more than anything else to extend its useful life.

Also, make sure your Airstream is level when you store it. That way, when you fire up the refrigerator before a trip to pre-cool it, the fridge will be level and will run more efficiently.

Keep the fridge as full as possible when you are using it. Whenever you take food out, replace it with water bottles, canned drinks, or something. The more thermal mass you have inside the fridge, the longer it stays cold, and the less often it has to start a new cooling cycle. This not only saves propane, it saves wear-and-tear on the fridge, too. You still need enough air space to allow circulation of cold air inside the fridge, but otherwise the more stuff and less air you refrigerate, the better.

[Erik Olson]

Protagonist,

Thanks for that good advice! I'll be sure to do these things as regular maintenance items on the new unit too.

In my original description, I should have said that the RM77 was right hinged. I don't know if that is factory configuration, but it was an unfortunate choice. The aluminum-edged bulkhead was dented from many run-ins with the freezer and refrigerator door. Hinging to the left instead allows the doors to open fully and flat against the pantry, where they can do no damage to themselves or the cabinetry.