Cleaning the Dometic Burner orifice

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   Somebody posted on here the directions on how to clean the burner orifice in the Dometic 8501 (sorry I forgot who it was) and it was a big help to me, but I wanted to make some changes that reflect the newest 8501 (2018 model) which appear to be different from the original poster's RM8501L:  (I used his original instructions today to clean mine (even though I don't believe it was dirty in a brand new camper but I've had trouble getting the LP to cool as well as the electric options)).  Thanks for walking me through it, but I needed to make some adjustments to your directions because of changes to the new Dometic.
Let me see if I can run through the cleaning steps I used here..... this refers to the RM8501L
1.  Remove the screw securing the sheet metal burner cover.  

2.  Use a 7/16" open end wrench to un-screw the gas pipe nut where it enters the VALVE assembly (NOT the burner).  I found that it is safer to remove the burner and pipe as one and disconnect the pipe from the burner in a controlled environment since the orifice is a little piece that fits into the burner and can easily fall out if you remove the pipe from the burner in the fridge recess. (I actually found the burner orifice does not appear to be a ruby with a hole in it and it can’t fall out.  It’s all one piece of brass with a hole in it just like a jet in a carburetor.) 

3.  Slide the burner assembly off the Flu  

4.  At this point, the igniter and flame sensor are still attached to the burner.  Remove the #20 Torx screw securing the igniter bracket and flatten the end of the burner where it passes through a slot in the bracket.  You’ll not be able to remove the burner until you do this.  The burner and pipe can now be removed from the fridge enclosure.  

5.  In a controlled environment (ie., where you can find stuff you drop), disconnect the pipe from the burner block and unscrew the 9/16” brass nut from the end of the orifice, then remove the orifice.   The orifice is the entire brass coupling with a tiny hole in the end with the 9/16” nut on it.  The hole is actually a ruby with a hole in it so that it does not erode from the gas passing through it.  There appears to be no Ruby nor removable tiny orifice.  It’s all one piece of brass with the number size of the Orifice stamped on it #65.

6.  I used alcohol in an ultrasonic cleaner to clean my orifice.  Not sure if you can just soak it and swish it around in a dish and get the same results.  

7.  Blow out the pipe with compressed air and also inspect the burner block to make sure nothing has made a home in there..... the burner block is where the gas jet mixes with air and then flows upwards where it ignites.  There is plenty of room in there for spiders and critters.  

8.  Remove screw securing the "T" cap from the top of the flue and remove the cap.  Remove the baffle that is suspended in the flue on a bent wire.  Pass a small bottle brush through the flue to make sure it is clean and un obstructed.  In my case I didn't have a bottle brush so I used a wadded up piece of paper towel and pushed it down with a plastic pushrod.  BAD MOVE..... it got stuck half way down and I thought I was in serious trouble for a while.  Not sure if there is structure in there or what, but I finally got it to pass all the way through and since it came out intact I figured all was well.  Finish off by blowing some compressed air down the flue if you can.  

9.  Re-assemble and test.  

My best guess is that stuff sticks to the edges of the orifice and slowly closes it off, gradually reducing the size of the flame.  Cleaning restores full flame.

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spydie Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 25 Jul 2017 Location: New Mexico Online Status: Offline Posts: 159	Topic: Cleaning the Dometic Burner orifice Posted: 02 Sep 2017 at 10:37pm
	Somebody posted on here the directions on how to clean the burner orifice in the Dometic 8501 (sorry I forgot who it was) and it was a big help to me, but I wanted to make some changes that reflect the newest 8501 (2018 model) which appear to be different from the original poster's RM8501L: (I used his original instructions today to clean mine (even though I don't believe it was dirty in a brand new camper but I've had trouble getting the LP to cool as well as the electric options)). Thanks for walking me through it, but I needed to make some adjustments to your directions because of changes to the new Dometic. Let me see if I can run through the cleaning steps I used here..... this refers to the RM8501L 1. Remove the screw securing the sheet metal burner cover. 2. Use a 7/16" open end wrench to un-screw the gas pipe nut where it enters the VALVE assembly (NOT the burner). I found that it is safer to remove the burner and pipe as one and disconnect the pipe from the burner in a controlled environment ~~since the orifice is a little piece that fits into the burner and can easily fall out if you remove the pipe from the burner in the fridge recess~~. (I actually found the burner orifice does not appear to be a ruby with a hole in it and it can’t fall out. It’s all one piece of brass with a hole in it just like a jet in a carburetor.) 3. Slide the burner assembly off the Flu 4. At this point, the igniter and flame sensor are still attached to the burner. Remove the #20 Torx screw securing the igniter bracket and flatten the end of the burner where it passes through a slot in the bracket. You’ll not be able to remove the burner until you do this. The burner and pipe can now be removed from the fridge enclosure. 5. In a controlled environment (ie., where you can find stuff you drop), disconnect the pipe from the burner block and unscrew the 9/16” brass nut from the end of the orifice, then remove the orifice. The orifice is the entire brass coupling with a tiny hole in the end with the 9/16” nut on it. ~~The hole is actually a ruby with a hole in it so that it does not erode from the gas passing through it.~~ There appears to be no Ruby nor removable tiny orifice. It’s all one piece of brass with the number size of the Orifice stamped on it #65. 6. I used alcohol in an ultrasonic cleaner to clean my orifice. Not sure if you can just soak it and swish it around in a dish and get the same results. 7. Blow out the pipe with compressed air and also inspect the burner block to make sure nothing has made a home in there..... the burner block is where the gas jet mixes with air and then flows upwards where it ignites. There is plenty of room in there for spiders and critters. 8. Remove screw securing the "T" cap from the top of the flue and remove the cap. Remove the baffle that is suspended in the flue on a bent wire. Pass a small bottle brush through the flue to make sure it is clean and un obstructed. In my case I didn't have a bottle brush so I used a wadded up piece of paper towel and pushed it down with a plastic pushrod. BAD MOVE..... it got stuck half way down and I thought I was in serious trouble for a while. Not sure if there is structure in there or what, but I finally got it to pass all the way through and since it came out intact I figured all was well. Finish off by blowing some compressed air down the flue if you can. 9. Re-assemble and test. My best guess is that stuff sticks to the edges of the orifice and slowly closes it off, gradually reducing the size of the flame. Cleaning restores full flame.
	2018 R-pod 176 2017 RAM 1500 5.7L Hemi

JandL Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 29 Mar 2014 Location: California Online Status: Offline Posts: 364	Posted: 03 Sep 2017 at 10:26am
	I just did a cleaning of my burner assembly on my 2012 trailer so it's the older model RM8501 refrigerator. I had the same problem that the refrigerator worked great on 120 volts AC but would not get as cold on propane. I also suspected my propane pressure regulator was not putting out the correct pressure of 11" of water (about 3/8 PSI). I replaced the cheap single stage regulator my trailer had with a two stage model. After that and cleaning the burner assembly everything is back to normal. You can defiantly see the flame in the burner assembly is fuller after the cleaning. I can also see on my stove stop the flame is slightly larger. I would recommend using an 11 mm flare nut wrench (6 point) to remove the nut on the end of the gas inlet pipe and a 1/2" wrench to hold the burner body. When I got mine out I soaked it in engine degreaser for a while and blew every thing out with electrical parts degreaser (CRC Lectra Clean). I then let it sit out in the sun to dry.
	JandL 2013 Honda Ridgeline 2012 177 2 Paynes in a Pod

spydie Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 25 Jul 2017 Location: New Mexico Online Status: Offline Posts: 159	Posted: 03 Sep 2017 at 11:06am
	There must be some different sizes on the older ones. Most wrench sets don't include an 11mm because it's basically a 7/16" wrench and I don't think the Rpod is built with metric equipment. There's only .0045" (45 ten-thousandths) difference in the two and yes, the 11mm is slightly tighter, but I'm sure that's a 7/16" standard SAE nut/gas pipe (same as a brake line). But a 7/16" wrench made for a flare nut (good suggestion) is always advisable (the right tool for the right job) as it does provide a better non-slip grip. Most of us get by with a 12 point OK. However, there's nothing on mine that takes the 1/2" you recommend. Mine takes only two wrenches, 7/16 and 9/16 and the #20 Torx. The dealer told me that he had tested the water column twice while talking to Dometic and it was "right-on" but then he also told me had cleaned the orifice (gas jet) and it was very obvious it had never been taken off (the paint that seals the threads so Dometic can tell if it's been disassembled was still in place on all the connections). So it just adds to the old adage that you can't trust anyone to work on your stuff but yourself. It's the only way you'll know it's done right. After cleaning the jet I'm seeing no difference. I might check into a double stage regulator. Is that one that's made for two bottles? or can you get a double-stage for a single bottle?
	2018 R-pod 176 2017 RAM 1500 5.7L Hemi

JandL Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 29 Mar 2014 Location: California Online Status: Offline Posts: 364	Posted: 03 Sep 2017 at 8:55pm
	From PurityPlus Specialty Gases web site "What is the difference between a single-stage and a dual-stage regulator? Single-stage regulators reduce pressure in merely one step to generate pressure within a specified range. Regulators created accordingly will display an insignificant variation in delivery pressure as the cylinder pressure decreases when in use. Because of this, single-stage regulators are most suitable for applications in which a constant outlet pressure is not vital, where an operator can monitor and readjust pressure, or where an inlet pressure is stable. Dual-stage regulators perform the same function as single-stage regulators; however, delivery pressure holds constant as cylinder pressure declines. Heightened accuracy in pressure control is maintained because the reduction of pressure is achieved in two steps. Dual-staged regulators are recommended for applications that require a constant outlet pressure for the life of a gas cylinder." The first stage lowers the pressure to around 10 to 15 psi and the second stage reduces it to 11” of water. The regulator I have is a 2 stage for a single tank, JR Products 07-30385 Low Pressure Two-Stage LP Gas Regulator (Fairview GR-9959). They do make 2 stage regulators for dual tanks.
	JandL 2013 Honda Ridgeline 2012 177 2 Paynes in a Pod

spydie Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 25 Jul 2017 Location: New Mexico Online Status: Offline Posts: 159	Posted: 03 Sep 2017 at 10:54pm
	Thanks. I just checked my 2018 Rpod and it has a Cavagna 2-stage installed at the factory, fully adjustable (maybe they all are?). So I've cleaned the jet and I have the 2-stage. There's nothing else I can do.
	2018 R-pod 176 2017 RAM 1500 5.7L Hemi