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Author Topic: Dometic Fridge & Rust  (Read 233 times)

bwatters60

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Dometic Fridge & Rust
« on: December 30, 2017, 12:27:24 AM »
Have an almost 10 year old Dometic RM2554 that has been used fairly regularly by the previous owner, and still works well.  The inside is in great shape but while inspecting the back side I noticed a considerable amount rust at the base of the flue/top of the burner housing.  This area also appears to be wet (fridge has not been used for several weeks, RV parked in driveway).  The flue top, the pipe coming out of the top of the flue, and the condenser fins also have quite a bit of surface rust.  I have detected no order of ammonia, and there are no signs of ammonia weeping.  My questions:

1)  Is the rust and wetness around the bottom of the flue normal?  I question this because I watch numerous videos of folks working on what appear to be older rv refrigerators and none appear to have any rust around the burner/flue.  Depending on feedback, I may order burner housing and burner housing cover.

2)  Is the surface rust on the piping, flue top, and condenser fins normal?  Would it be wise to lightly wire brush and paint the pipe to deter further rusting?  If so, would a high temperature paint be required?  Any recommendations appreciated.

Thanks in advance!

Bruce

Gary RV_Wizard

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Re: Dometic Fridge & Rust
« Reply #1 on: December 30, 2017, 09:55:29 AM »
Rust in those areas is common, but the rust in your burner area looks severe, much greater than typical. I too would be concerned, but the bad area looks like gas pipe and burner, not the ammonia tubing. The burner area operates at about 350 F, so corrosion there is expected. Usually the burner components last15-20 years, though, and many have survived 30+.

An ammonia smell is possible if there is a leak, but not a reliable indicator if not present.  Ditto for a yellow powder.  The first thing that escapes in a coolant leak is hydrogen gas, which is odorless and leaves no residue.  Cooling deteriorates badly as soon as the hydrogen leaks off and box temperatures go into the high 40's or  50's. If yours is still cooling, you don't have a leak. Yet.

Some of that rust is just on the outer shell of the burner, essentially a metal shield. It is probably replaceable.  You don't need any special tools on an absorption fridge - there is no compressor or user-replaceable pressure connections. The entire ammonia chiller is self-contained, sealed and bolt on. You can replace the entire thing with hand tools.
« Last Edit: December 30, 2017, 09:59:49 AM by Gary RV_Wizard »
Gary
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Gary Brinck
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