Around 10 years is about the typical life of a RV fridge so you're about the right age for a replacement cycle. I guess the way to look at it if it needs to be replaced is that it doesn't owe you anything at this point. 

Do not use a wire brush to clean the orifice. Use 93% isopropyl alcohol or denatured alcohol to clean the orifice. Compressed air works for the burner slots, but a soft brush with some alcohol wouldn't hurt there either.

For the flue, remove the top angled cap of the stack. You can then pull the spiral insert out and clean it. If you can get a bore brush down into the stack, you could brush that out. Otherwise, compressed air. Once things are clean (use a light and mirror to check),

One more step may be needed given the age of the trailer. Disconnect the propane line at the refrigerator and at the regulator. Place a container under the end of the hose at the regulator end. Use compressed air to blow the oily residue out of the propane line. I've done this a couple of times when my refrigerator was not working well. Reconnect, leak test, and purge the lines. It may take several cycles for the refrigerator burner to light as that branch of the line will need to purge the air also.

If all goes well, your refrigerator should be back to working well on propane again.

So the report is in!  Fridge running on shore power with battery running the 2 muffin fans.  Temp dropped just under 3.5 degrees/hour.  Fridge running on shore power with battery running the same fans.  Temp has dropped degrees/hour.  Started running at 3 pm with interior temp in fridge 92 while outside temp was 94.  At 9 pm temp has dropped to 67 degrees in refer or 4.16 degrees/hour with outside temp at 78.  HOPEFULLY by morning things will all be well. 

Took angled cap off stack and removed spiral inset out - no need to clean - appeared nearly brand new.

Tapped on chimney stack - nothing came out.

Removed the combustion chamber with a 7/16 and 1/2 inch wrench.  Tried to tap the orifice out - no luck so i used a product called "Citrol" by Schaeffer's and soaked it for a couple minutes and blew out with compressed air.  Blew out combustion area as well as orifice both directions and also the area where the flame comes out of combustion area - appears like a 1/8" diameter bullseye surrounded by several much smaller holes.  Blew out some crud but not much.  Will see in the morning if I have a similar temp as the electric gave.  If not, I will remove the propane hose and blow out with compressed air to see if any oil comes out.

Thank you mcarter, offgrid, and Stephen H.  This is what makes this forum so great, having a bunch of well learned individuals who willingly help those like me who haven't arrived there yet.

Here we sit with fridge running on propane for 19 hours.  Setting is on 4 of 5 dots, 5 being the coldest.  Temp has stabilized at 41 degrees, not near as cold as when I was on electric where it went down to 36.  However the fridge side is sitting in the sun and current ambient temp outside is 92 and I also checked inside the freezer and it was able to make ice overnight during the past 14 hours.  So what temps do you all have when running propane?  Is 41 acceptable or do you think this is on its way out because it is nearly a 10 year old unit?  The only thing I have left to do is to take off the supply line  from the regulator to the fridge and see if there is any oil or residue to blow out.

By the way my pod is a 2011 and it works just fine

https://postimg.cc/CRvQW5tW">

https://www.slideshare.net/IanLouiseCelestino/simple-vapor-absorption-refrigeration-system - https://www.slideshare.net/IanLouiseCelestino/simple-vapor-absorption-refrigeration-system

If you go to around slides 17-20 you can see that the COP of an absorption fridge is related to three temps (To-condenser/absorber), Te -evaporator, and Tg -generator). I didn't run the numbers, but since To (essentially the ambient temp) is showing up twice, in the denominator in one case and subtracted in the numerator in another) COP is going to fall off quickly with higher ambient temps. And if COP drops cooling capacity drops along with it. To run the numbers you would need Tg, essentially the hot air from the propane flame or electric element. I found one reference for that which is around 350F. Note that you would need to do this calc in degrees above absolute zero (Rankine or Kelvin degrees), not in F or C. 

The reference with the Tg of 350 was this, which is an interesting discussion of what causes damage to RV fridges and how to prevent it. 

https://myamericancoach.com/wp-content/uploads/2018/02/ARPRV-Absorption-Fridges.pdf - https://myamericancoach.com/wp-content/uploads/2018/02/ARPRV-Absorption-Fridges.pdf

Originally posted by marwayne Jato, Cleaned up the fridge outside and turned it on, went from 23* C to 6* C in about 4 hours on LP

That was the good news as the next day the fridge temp went up to 57 during the daytime with outside temperature at 95.  Fridge was in the shade, facing north.  Had my son with grandkids up for the weekend.  He had to show off his new 25' speedboat so we spent most of the weekend tooling around on Torch Lake, plenty to see on a lake that is over 19 miles long. 

Now that they left I can get back to business.  I took off propane lines and blew them out from the regulator to the combustion chamber.  Let the combustion chamber part sit in mineral spirits for 20 minutes and blew out with compressed air.  Then did another stint with WD 40 soaking it well, letting it sit for 10 minutes and then blew that out.  Assembled everything and fired up about 1 hour ago.  Outside temp is 84, fridge temp has dropped from 86 to 83.  Will see if anything improves after all this fussing, which I rather do than purchase a new fridge!

One other thing that could be happening is that the pressure of the system might be low. If I recall correctly, the pressure should be 11" water column. I've seen instructions on how to make a tester. There is a small threaded port in the junction where the flexible hose ends that has a plug in it. That could be used to attach a tester.

You could try replacing your regulator and see if that makes a difference. They can go bad over time and not allow the proper pressure.

Thanks Stephen.  Never thought about a faulty regulator.  The one I have is the original from January 2011.  IF the regulator is bad wouldn't I see a problem running the burners on the stove or a lack of heat when the furnace runs?  Also is there any way to check or test the regulator to see if it is in proper working order?

Update on fridge temp.  This morning at 6:45 fridge temp got to 37, fantastic.  However now it is 10:30 am and it now reads 39.  However I also have a thermometer sitting a few inches from the refrigerator lower grill in the direct sunlight and it is reading 98 so hopefully that is why the temperature is rising.  In a couple hours the sun will be far enough south so the fridge side will be totally in the shade for the duration of the day.

If it got down to 37, then it is likely working well. The only way I know of to check the regulator is to do a pressure test. You could purchase one from Amazon or make one. The site linked below talks about making one. The actual instructions are linked within the page.

http://www.loveyourrv.com/building-simple-rv-propane-leak-tester-u-tube-manometer/ - http://www.loveyourrv.com/building-simple-rv-propane-leak-tester-u-tube-manometer/

Edit: This is the link for how to build a manometer:

http://www.rverscorner.com/manometer.html - http://www.rverscorner.com/manometer.html

https://www.truckcamperadventure.com/rv-refrigerators-how-level-should-they/#:~:text=As%20mentioned%2C%20gravity%20is%20critical,coils%20to%20cool%20the%20refrigerator.&text=Today%2C%20Norcold%20recommends%20that%20their,level%20front%2Dto%2Dback. - https://www.truckcamperadventure.com/rv-refrigerators-how-level-should-they/#:~:text=As%20mentioned%2C%20gravity%20is%20critical,coils%20to%20cool%20the%20refrigerator.&text=Today%2C%20Norcold%20recommends%20that%20their,level%20front%2Dto%2Dback.

Oh yeah...minor detail.

Well, at least my post may function as a public service announcement to folks who may not have realized how important a level RV is to fridge function...

Finally able to report back after a few days of testing.  Running electric I found fridge temp at 6 am 35-36 @ 6am going up to 48 - 50 during the hottest part of the day 2-4 pm where temp would rise to 48-49 degrees.  On the propane side fridge temp at 6 am would be 35-39 and at the hottest part of the day 2-4 pm temps would be 49-51.  This was done with a totally empty fridge with the exception of a pan of water placed in the freezer in the evening - each time under all circumstances ice would be made by morning.  Outside temperature during the hottest part of the day varied from 90 - 95 F.

My next test is to find out if these are normal operating temps with the existing outdoor temps and putting pre-cooled items (water and beverages) inside so that it isn't totally empty.  It will now be 50% filled with the above - will be interesting to see if this will allow the interior temps to be more stable during those hot parts of the day.

2 questions still emerge.  Are these temps that I give 'normal'?  Are these similar to what your temps are under somewhat similar conditions?

I have been told that the electric mixer valve may be faulty, that when I turn up the call for colder temps, (eg. - from 3 to 4 bars or 4 to 5 bars) that I should observe a larger flame which will produce more heat to cook the ammonia more vigorously giving me a colder temp.  When I went from 4 to 5 bars I did not observe a larger flame, it appeared to my eyes the same size.   Is that true, have you observed a larger flame when doing this?   Thanks for your patience, this has been quite a learning experience thus far.

What I would tentatively conclude from that is that your gas and electric sides are both working about equally well, and obviously the fridge is cooling. Where I'm heading is I'm not sure there is anything wrong with it at this point. 95 is hot, it might not be able to maintain really cold temps is all. 

I think you're on the right track by adding more cold water/ice to the fridge. That will definitely help  stabilize things more. Water (or any kind of drink) has very high thermal mass (1 btu per lb per deg F to be precise, and 144 btu per lb to melt ice). If you put say cold canned drinks in there (compared say to a gallon jug) you will also have a lot of surface area to transfer heat between the water in the cans and the air in the fridge and that will help keep the afternoon temps in there lower. Try it and see, but as you say, put the liquids in cold and give it a couple of days to re-stabilize.   

The thermostat works similar to your fridge at home, the cooling unit runs longer, or maybe continuously, to cool the interior when you set the unit to a 'higher' setting, which is a cooler temp.

You might try moving the thermistor on the cooling plate, or adding one of those little battery powered RV fridge fans inside the fridge, or adding an extra 12v fan on the exterior condenser fins, all of these can help, but otherwise these units are not the most powerful fridges ever made. On the other hand they sip propane...extending our ability to stay 'out there'...

+1 to Podwerkz. I added a cooler similar to this one to the inside of mine:

https://smile.amazon.com/DutchAire-RV-Refrigerator-Fin-Fan/dp/B089BWZ3PX/ - https://smile.amazon.com/DutchAire-RV-Refrigerator-Fin-Fan/dp/B089BWZ3PX/

I also had a couple of muffin fans from computers in the house and I added them to the outside top cover, set to blow out to help extract hot air from the rear compartment. between the two, my refrigerator seems to keep temperatures better provided I periodically clean the propane system. Still, on hot days, especially with the sun beating down, the temperature in the refrigerator will rise into the 40's or 50's, especially if the AC isn't running to help keep the inside of the 'Pod cool. The heat coming from all sides is just too much for an absorption refrigeration system to handle. It would probably need twice the insulation to be able to keep cool in 90+ degree temperatures.

OTOH, I was able to purchase a Free Piston Sterling Cooler which operates on 12V, either from an automobile style 12V plug directly or through a transformer for AC power use. This thing is able to keep right around 4C (about 39F) even in high 90's temperatures. It was used by drug companies for transportation of medications (no biologics or organs), and was donated to ReStore where I purchased it. Unfortunately, it is nearly impossible to find new ones at any sort of reasonable price. It is very efficient, and will not kill the battery overnight as it takes much less power to run. The newer Danfoss compressor refrigerators are also supposed to be efficient enough to use, but I have no experience with them.

Yeah, there are 12V positive and negative wires or terminals, but the windings of the compressor are something else. Otherwise, with typical 12V DC motors, we would need brushes and commutators, and these compressors do not normally have those.

Although, I have not torn into one to verify that.

At any rate, I did the typical solar powered fridge experiment most of last year...I found that to have more compromises than a propane powered fridge. Just sayin.

IIRC (which I might not, it was 35 years ago) the Secop controllers provide low voltage square wave output to the hermetically sealed compressor motor. So they are a kind of inverter, just like brushes and commutator are a kind of inverter. That is what a brushless DC motor design does, it replaces the com and brushes with transistors do the polarity switching, based on a position sensor within the motor. You can't hermetically seal a brushed motor so this was the solution. The variable frequency 3 phase AC motor drive systems were originally developed for big industrial motors and have now made their way into EV's. But for a little bitty fridge compressor those are overkill, at least so far. 

You got a steal of a deal. Keep it nice, it might be a collector's item before too long. I don't think you can get a FPSC now, except for high end computer builders who spend big bucks to buy tiny ones to cool their overclocked CPUs to -40C or some such craziness. 

You can't compare the Dometic on 12V to the Danfoss, the Dometic absorption cycle COP is probably around 0.5 vs around 2 for the Danfoss (or FPSC). The absorption fridge is terribly inefficient but there is so much energy content in propane that it more than males up for it RV applications. 

I wasn't comparing 12V FPSC to propane Dometic, but 12V FPSC to Dometic on 12V. That is why I will continue to use the Dometic on propane when not connected to shore power or towing and use the FPSC to supplement for meats and other things that really do need to stay cold, even in hot weather.

Back to the OP.  Yesterday with the fridge 1/2 full with water and beverages the temp during the daytime stabilized at 43-44 degrees which is better but the outside temp was cooler as well, only getting up to 88 degrees.  This morning at 6 am temp was sitting at 42 which didn't please me as outside temp was 74. 

Decided to clean combustion chamber yet once again in light of all this fussing.  Turned to electric, causing the fridge temp to drop from 43 to 36 degrees in about 3 hours.  Let combustion chamber sit in mineral spirits for 2 hours and then blew out with compressed air and re-inserted.  At noon I turned off the electric (fridge was at 37) and turned propane back on.  Here it is 3.25 hours later and the temp has not changed, outside temperature is 80.  So things are looking up at this point.  Trying to figure out if there may still have been some crud either inside the combustion chamber or inside the orifice - doesn't seem likely as both had been cleaned out 2 times before doing it again this morning.