A few Dometic RM 8505 Refrigerator observations and opinions

[Excel]

Absorption refrigerators have been improved in the last few years. The 8505 Operating Instructions make no mention of having the refrigerator level during use. The warranty does not require level operation. The refrigerator works best when level and Dometic wants us to try it level before calling them for help with problems.

During a failure to cool using propane, the 12 vdc mode worked great while driving until we could obtain an ice chest. I think that the 12 volt mode is now getting a bum rap. (The refrigerator propane valve was our problem.)

While trouble shooting my cooling problem, one Dometic failure pointed out in their service manuals that got my attention was the burner flue tube becoming unwelded from the boiler. Burner works great, but no heat is transferred to the boiler.

I drive with the refrigerator on propane when a cluster of vehicle stops is anticipated.

I drive with the refrigerator on propane when charging the coach battery is a priority.

Refrigerator temperature seems to increase a couple of degrees over the stationary temperature when driving with the refrigerator on propane. I have not checked 12 volt operation temperature differences.

When all of its parts are working, this refrigerator performs better than expected; as during occasional unlevel and higher elevation operation. When you consider that the closed cooling system contains water, ammonia, hydrogen gas, and a corrosion inhibitor that you add heat, gravity, 12 vdc control, and ambient air to, and then it can make ice cubes; it is like magic.

Chuck Sorensen
Buellton, California
2012 PW Excel TS

[markopolo]

Thanks for the info Chuck. The 12 volt mode may be getting a bum rap like you say. I always thought of it as being useful to maintain an already cool fridge. I'm still a fan of absorption fridges for the versatility they offer.

My van has an older Dometic fridge and the 12v wire is neatly coiled having never been connected. The older fridges don't need 12v for operation. I run the fridge off the inverter when driving and can turn the inverter on or off from the drivers seat. The fridge uses approx 10 amps DC when running off the inverter.

I had trouble with cooling on propane on my last trip and haven't investigated the cause yet. It might just need a cleaning. If not I'll check the refrigerator propane valve and burner flue tube welding you mentioned.

[stanw909]

Yes. Good report.