87 Sovreign 25' - fridge issues

[triptick]

We have a 25' Sovereign which has been in our family forever. The fridge doesn't seem to be able to keep things cold when running on LP when the temperatures outside are higher than 25C (about 77F) so we rot things fast. If we have a full hookup and run the AC things work better as the duty the fridge needs to do is lower. We are considering replacement as it is original, as are most things in the trailer. Are there brands that are more suitable for airstreams out there, so we can start to price it out? We are in Canada and there is no AS dealer within 1000 km so getting help from a dealer is out of the question most likely.

Thanks in advance for any advice or assistance.

[JohnBarth]

I started having the same issue on my '87 Sovereign 25' with an original Dometic RM 2600 about a year ago. Works very well on 120 VAC - freezer plate ices up, nice and cold in the fridge space, but barely cools at all on propane. This model doesn't have a DC only option.

First off, if it works good on AC power you know you have a good ammonia and hydrogen charge, and you're level enough for it to work correctly in either mode.

I checked and saw I had what looked like a decent flame on the burner, so I knew gas was getting through. But the ammonia absorber and piping between the boiler and the absorber wasn't heating up.

I blew out the burner tube and cleaned it with alcohol, removed the orifice, cleaned it with alcohol and reinstalled it. Started it back up on propane and checked the flame - maybe a little better but hard to tell in the daylight. But after two hours it's making ice in the freezer and the fridge is down to about 55 F.

This manual is helpful, as is this parts list.

[n2916s]

When my RM2800 did this on my previous trailer, a 1986 Sovereign, I pulled the reefer and cleaned the flue.

1. Pull the reefer into the aisle.
2. Remove the spiral baffle from the top of the flue
3. Use a 12 gauge shotgun cleaning brush (the kind with the 12” rod segments that screw together) and clean the flue. You might want to have someone holding a shop vac nozzle at the bottom of the flue as you will be amazed at what comes out.
4. Reassemble, reinstall, enjoy cold ops on gas.

[JohnBarth]

Originally Posted by n2916s

When my RM2800 did this on my previous trailer, a 1986 Sovereign, I pulled the reefer and cleaned the flue.

1. Pull the reefer into the aisle.
2. Remove the spiral baffle from the top of the flue
3. Use a 12 gauge shotgun cleaning brush (the kind with the 12” rod segments that screw together) and clean the flue. You might want to have someone holding a shop vac nozzle at the bottom of the flue as you will be amazed at what comes out.
4. Reassemble, reinstall, enjoy cold ops on gas.

Thanks for this! I was inquiring on another thread how to access the flue since the cover on top of the trailer is riveted in place and provides no access to clean the flue or pull the baffle.

Couple questions:

1. Is there enough clearance between the top of the flue and the ceiling of the trailer to pull the baffle out inside the trailer? Likewise getting a flue brush in? Or do I just lay it on its side once out - or would that mess up the ammonia/hydrogen charge?

2. How is the fridge flue connected to the vent that goes out through the roof? In residential applications I'm used to B-vent piping, high temp caulk and foil tape....

3. I've never pulled my fridge out in the 10 years I've had my trailer. Any special tips/tricks or gotchas to be aware of?

Thanks again!

[JohnBarth]

Update here:
I removed the orifice again and this time also removed the burner. I soaked both in alcohol for a few hours while I checked the flue.

I cleaned out the flue from the bottom with steel wool, then blew it out with 40 psi air. Never got any soot, corrosion or anything else out. The internal baffle moved freely.

I cleaned every trace of carbon off the thermocouple, igniter and burner with 220 grit metal oxide sandpaper wetted with alcohol.

Put everything back together and lit the fridge on propane. Per my infrared thermometer it’s cooling down as well on gas as it does on 120 VAC (Freezer plate is about -21 F on the back, -11 F on the front. Fridge fins vary from 14 F to 28 F). Glad I didn’t try to remove the fridge - I've heard from some that it's a real PITA.

[n2916s]

Sorry I didn’t respond last week. I am presently living in an area with zero cell coverage so only get to check in occasionally.

Sounds like you have solved your problem,.

Well done!