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bobk3d · 08-21-2019, 11:37 AM

The other day, I woke up and found my refrigerator temperatures were very high, both fridge and freezer. I think there was a slight ammonia smell, so I shut it off immediately. But I was a faint smell, and I'm not 100% sure it was ammonia.

I checked the back, and everything looks good. I had a cooling unit break a couple years ago, and there was visible yellow residue, so I know what to look for. Right now it looks really clean.

So my question is... is there a safe way to diagnose it? If I turn it on and keep a close eye on it, will I smell ammonia before it blows up? Is there any other way to check for proper operation? Anything else I can inspect for problems besides the base of the boiler?

Unfortunately, my budget does not have a line item for "coach burns to the ground."

Old-Biscuit · 08-21-2019, 11:55 AM

Both freezer & food compartment temps WARM.......slight ammonia smell

Ammonia can disipate fairly quickly especially if tubing leak is up high in cooling unit vs in boiler section
Yellow residue is only visible when boiler section (perk tube) cracks as that is where the water is separated from the ammonia solution.
Yellow residue is from the sodium chromate in solution (anti-rust inhibitor)'

Up higher in the cooling unit.......ammonia and hydrogen
Leak higher up......300 PSI hydrogen/ammonia-------pssst then gone

I suspect your cooling unit has DIED!

You can try to run it on AC but I believe you will find that the freezer/food compartments will NOT cool down .........after 4 hrs the back wall of freezer should be cool to touch.

Gary RVRoamer · 08-23-2019, 09:18 AM

You will have visible yellow residue in only a modest percentage of cases, so lack of it doesn't prove anything. When there is a cooling unit eak, the first thing to go is the hydrogen gas and that is colorless and odorless. You usually loose the fridge box cooling as soon as that is gone. Then the ammonia gas evaporates and the freezer quits too. The ammonia may also spew enough sodium chromate to leave the yellow, but more often the ammonia just evaporates into the air.

BigEvi · 08-23-2019, 10:10 AM

I just removed a working Norcold 1200.

Dont know where you're located but if you're anywhere near PA you can come get it

-E

bobk3d · 08-25-2019, 08:04 PM

Hmm, the fridge has been off for six days, but this morning I smelled that smell again, and realized it was chlorine, not ammonia. I sanitized my tanks recently, and used too much bleach, apparently it hasn't entirely cleared out even after a flush cycle. As I think about it, I've caught a whiff of chlorine in the shower, too.

So perhaps the fridge just failed on electric mode. Or maybe it just wants to restart, or has a bad control panel.

If I turn it on to test it, what should I look out for? Stand outside and stare up (or down) the vent for a couple of hours while holding a fire extinguisher? Any other suggestions?

Arch Hoagland · 08-25-2019, 08:17 PM

Year, make and model of refrigerator would help.

Old-Biscuit · 08-25-2019, 10:51 PM

You have AC Power available?

YES......
Check the 120VAC Outlet fridge power cord plugs into.....does it work?
NO.....tripped circuit breaker
YES......
Check the fuse on lower circuit board....will be a GLASS Fuse either 5A or 8A
Measure it for AC Voltage on BOTH ends of fuse to verify it is good

Turn Fridge ON.......need DC (do you have lights on upper panel, fridge light work)
Selectric AUTO and let fridge run for 12Hrs minimum on AC.
AFter one hour check that canister above burner area is getting warm
After 2 hours feel the absorber tubes (large slanted tubes) and the absorber tank...should be warm
After 4 hrs..feel the back wall of freezer...should be getting cool to touch
After 6 hrs...feel Fins in food compartment...should be getting cool

***Do NOT hold doors open for any length of time...just a quick open/touch/close the doors

After 12 hrs...freezer should be COLD and food compartment should be very COOL

If not........
Unplug thermsitor leads (temp probe on FIN in food compartment) either at lamp assembly or on lower circuit board (model dependent)
Run fridge for another 12 hrs
COLD/COOL..........bad thermistor
NOT Cold/Cool........could be circuit board or cooling unit is bad.

More testing would be needed.

Brand/Model would be helpful

bobk3d · 08-26-2019, 12:32 AM

Thanks, that will be very helpful.

It's a Dometic RM3862.

Cooling unit was replaced November 2017.

bobk3d · 08-27-2019, 06:54 AM

Well I turned it on electric and checked the back vent. I smelled something, even before I turned it on. Not sure if it's ammonia, it's been a long time since I smelled that.

I'll ask a friend for a second opinion, but for now it seems too dangerous to leave it running.

Thanks for all the input.

Side note... I picked up a mini fridge to get by. The coolant is cyclopetane, supposedly very flammable. Big warning label on the back.