Troubleshooting my older 3-way fridge

[markopolo]

Good guide available to download from Bryant RV ( http://bryantrv.com ) here: http://bryantrv.com/docs2/docs/rm2510_52.pdf

Two photos of the parts on my fridge (RM2410) with covers removed.

jet.JPG

bypass screw.JPG

My fridge stopped maintaining the temperature when on the gas setting. It worked fine on AC.

I cleaned the burner and flue as best I could with a brush and a vacuum. I could not figure out how to remove the burner In my defense it was just a few degrees above zero when in the garage when I worked on it. I'll try to figure it out another time. It didn't look dirty so I didn't think that was causing the fridge problem.

Smaller diameter hose attached to Shopvac

rubber hose attached to shopvac.JPG

This fridge has a mode selector switch (Elect, 12V, Gas, Off) and a thermostat control (Off, 1,2,3,4,5,6,7, Max). I found that the flame would extinguish when the thermostat was set to Off. That shouldn't happen. The thermostat off setting should result in a very low flame on this fridge as the basic operation in gas mode is normal flame or low flame (normal or bypass). The flame size doesn't vary if the thermostat is set to 3 or 7 for example. The duration of the flame will vary. When the fridge temperature matches the thermostat setting the thermostat switches to bypass mode (same as Off position on thermostat dial).

With the main gas valve shut off, fridge off and unplugged, I removed the burner jet and soaked it in alcohol, dried it out and replaced it. No real improvement.
Next, I removed the test port plug and was surprised to see some debris collected there. I vacuumed that out. I also removed the bypass screw and soaked it in alcohol after removing the tiny O-ring. I dried the bypass screw, put the O-ring back on and reinstalled it.

Next to do was a gas pressure test using a DIY U tube manometer. Like this: http://www.rverscorner.com/manometer.html or http://www.redroverroadtrek.com/FridgeManometer.html

The gas pressure was low when the water heater, fridge and stove burner were all running. I set the propane regulator to 11" water column when two stove burners and fridge were all on max settings. The gas pressure drops below 11" WC if I add the water heater but is 12" WC if only the fridge is running and I didn't want to set it higher than that. I did not start the furnace during the testing - that would make it drop more. A bit of a compromise and best guessing. It would be rare to have all propane appliances running at the same time in my RV.

Long story short - the fridge flame seems to be working as it should now. The flame does not extinguish when it goes into bypass mode. There is a low flame when the thermostat is set to Off and a normal sized flame when the thermostat is set to 1,2,3,4,5,6,7 or Max. That's how it should work. I plan to replace the regulator as I discovered it is an older single stage unit. Newer regulators are two stage and should do a better job at delivering a steady 11" W.C. to the appliances.

Leak test propane fittings after doing any work on them.

[markopolo]

The fridge worked great on a recent trip I was able able to set the thermostat to any position on the dial - even off (on thermostat) - without causing the flame to extinguish. If you have a 3-way fridge that isn't performing as well as you expect I suggest working through the troubleshooting steps in the service manual. If you have a tech do the work I'd use the troubleshooting steps as a checklist.

[kellyllek]

marco thanks for the reply and info ! . I see that it's not uncommon for the 12v fridge to kill the battery! I did get plugged in a few days and the battery came back to normal.

However, the fridge; I have a dometic with the piezo lighter. I thought I'd get to it all through the front and attempted (before I saw the guide) to remove the front. Alas there was no access to the burner! I didn't realized the little indicator reflector I guess is showing the flame from the back ?? !! Anyway, I could not get in, and worse, when I put it all back the thermostat just spins around and I'm not sure it's doing anything. that said when plugged in it seems to be at the perfect temperature.

but the propane is still not working. Sadly I've only looked a little bit and I still dont' know, even from the manual posted, where the burner and flue and such are? Are they accessible in the back? I fear this job may be beyond me, but I can also tell you I have to get the fridge back on propane otherwise boondocking happily will not be possible.

meanwhile, I upgraded my inverter to a 700 watt continuous. It also has a monitor of sorts on it. I can see the last couple days without plug-in and extensive use of the electrics it's getting to about 11v. The inverter will whine at 11, soI know I need to recharge the batter but I'm not plugged in and not driving. I'm starting to feel that a solar system would be pretty good for me, as all the hours I'm not driving and not even in the van the solar would be trickle charging it.

alas the 700watt inverter seems to fit all my needs, except it's cooling van whirls away at ever changing speeds! If it was one consistent speed once in a while, it be great, but over 5 seconds it'll go "Whoo, Whoooooo, WHOOOO,woo, woo WHRILLLLLL!!!! drives me crazy!

I wonder if I get a bigger more amplifier looking inverter dothey all have fans? Or are any like a large heat sink that can remain silent? I can always put a volt meter or other monitoer onto the system, though it's pretty cool being able to look at the volts right on the machine.

I would have gotten the inverter months ago but knew Amazon had it $20 cheaper than Walmart, but I've had little access to Amazonon the road... I was lamenting this fact to a dude at Walmart when he told me that match Amazon Prime prices! dang I wish I knew that when I started!

anyway, this inverter has mixed reviews: http://www.amazon.com/Schumacher-XI7...rter+shumacher


meanwhile I think I may invest in this solar system: http://www.amazon.com/Renogy-100W-Mo...0w+solar+panel

It looks like I can put it right behind my fantastic fan, of course I'd have to check the size and see how to install it onto the roof. http://roadtreking.com/minimal-solar-system/

[markopolo]

It's time to get a tech to look at the fridge to get it set up perfectly. I had the front panel off on mine when I redid the flooring and had the resulting spinning knob I got it back in place with some fiddling. From memory, I think it has a "D" shaped socket on the end so you have to line it up by feel and then insert it. Get the tech to check the gas system pressure at the same time.

A larger inverter for small loads may not be the way to go. Figure out the largest load in watts you plan to run and add a cushion like 50% or even 100%. Example: If the largest load you plan to run is the laptop at 100 watts then a 200 watt inverter would be fine. I'd choose a smaller Pure Sine Wave inverter rather than a larger Modified Sine Wave inverter. You might find that the laptop power brick gets hotter than usual when run on a Modified Sine Wave inverter.

[Begreen]

Roadtrek provides access to the rear of the Dometic refrig with a removable outdoor vent grille. On some models the access is great but unfortunately on others they have the access grille offset by about 8" from the burner assembly . That means the refrig needs to be pulled to service it. Lame RT!

The older Chevy RT versatile had great access. Our 2002 Dodge Versatile has the lousy offset access door. Which do you have?

[Begreen]

The sluggish performance of our Dometic 2353 made me think the burner was clogged. Unfortunately on our vehicle you can't check this in place. Once it was out of the cabinet I did some testing with the refrig on level ground. First I checked the burner, it was clean and looked like it had recently been serviced. WTH? So I hooked it up to a propane cylinder and tested how quickly it could cool. In multiple tests it achieved a 20 degree temperature drop in about 3 hrs.. No problems noted at all. Then I reinstalled the refrig and tested again. So far I have only run one test but it took 5 hrs to drop the temp 15 degrees. By this morning the temp had dropped 30 degrees. So the refrig appears to work much slower in situ.

I need to run the test again in the daytime but I am thinking that Roadtrek's cabinet design is the cause for the sluggish performance of this refrigerator. Some noted issues:
• The exhaust heat is not separated from the condenser heat. In our Eurovan camper the exhaust had an independent exterior outlet. It cooled faster, about like the Dometic when out of the RT cabinet.
• There is a stiff plastic flap right above the absorber coils. Not sure why, but it would appear to slow down convection air from cooling the condenser fins and force more warm air to be pulled from the exhaust stack area.

Has anyone else looked into this or made any mods to bring the refrigerator performance up to its full capabilities? I've read of some interior fan mods, but so far haven't found info on improving ventilation over the condenser or isolating the exhaust heat.