1997 Norcold Model 982
I just bought this rig with the above frig. I intend to replace it with a residential but am using it for now. (on a 3,500 mile trip) Just to be safe, before we left I installed an ARP device and cleaned the burner and orifice.. Anyhow, it works as it should with a nice blue flame EXCEPT the flame kind of spits. i.e. as if it momentarily loses its gas supply. It continues to cool but I can hear a continuous shhh-t-shhh-t-shhh... from inside almost like a perculator. From the outside I can see the flame stutter. The only adjustment I see is a little air shutter but it doesn't seem to make any difference.
I should add that the other LP devices (water heater, 4 burner stove and furnace) work fine. Any ideas? Thanks.
jor
(also posted on rv.net)
read the part about cleaning the orifice.
Burner Orifice Removal & Cleaning - Norcold 962 Operator's Manual [Page 13] (http://www.manualslib.com/manual/112574/Norcold-962.html?page=13)
Did a good job on that. I don't think this frig has seen much maintenance as it was pretty cruddy but I am familiar with the process and got it nice and clean. I didn't have time to clean the flu but the burner and orifice looked good. Thanks.
jor
Just noted something. If I blow gently into the burner area the flame behaves properly. It's like it's running a little rich or something. It's cooling OK but it can't be efficient with this flame behavior.
jor
Have you checked propane pressure? If set a little high, mixture can be rich.
Same affect if you are at high altitude-- less air to propane.
Post a pic of the main propane regulator located in the tank area, show the markings on top of the hex cap.
Brett and Nancy,
I'm thinking this might be the right track. I'm thinking the regulator could even be the original. Anyhow, I'll take a photo mañana. I was assuming that because the other devices were working well that the regulator was OK. Anyhow, thanks. More to follow.
jor
John, how about adding a large metal cover to better keep the flame from being affected by air flows from vent (or fans).
You need a manometer check gas pressure at appliance test port it should be 11'' water column with half of the other appliances operating. adjust regulator as needed. Then proceed to check all other gas appliances pressure.
Because of the small flame size, the refrigerator is the most sensitive device to incorrect propane PSI.
If it is too rich, it IS either too much fuel or too little air. If the burner tube is clean and not rusty, that points to propane pressure or propane jet as the next likely suspects.
Yes, if someone used something hard to clean the propane jet, the orifice may have been enlarged. So, if propane pressure is 11 column inches of water, burner tube is good, and you are not at high altitude, replace the jet. Easy and inexpensive.
Could have happened in the past as the frig displayed the same issue before I cleaned the burner and orifice. As far as I can tell, the frig hasn't had good maintenance. Thanks.
jor
Check or change out igniter if problem persists.
Tony,
Would like more information on this one. It is my understanding that the igniter which on many also serves as the thermocouple is either GOOD or BAD. No "variable" flame.
Another vote for checking the LP pressure at the fridge with a manometer. Also check the fridge baffling by taking off the top vent on the roof and looking down. You want to make sure none of the baffles that form the chimney have worked themselves loose over the years, or that you don't have nests created by some critters.
You can build your own manometer (lots of instructions available on the internet), or purchase one. There should be an LP test port on the back of the fridge accessible through lower external vent.
The fridges can operate between a pressure range with 11 water column inches being the lowest.
With our previous coach all the appliances worked fine but the fridge was not cooling at all. I tested the pressure and found it at 5 water column inches! The regulator (a cheap one) had filled with oil that precipitated out of the LP. The oil essentially clogged the regulator.
I replaced the regulator and used Rectorseal #5 (the yellow stuff) on all the joints, retested the pressure at the fridge, and adjusted the regulator to 11 water column inches at the fridge with 50% of the LP appliances running. The burner flame sounded like a jet engine compared to what it had been. The fridge cooled like a champ!!
Good luck.
Chris
I happened to ask Keith Davis to show me the parts of our Dometic, how it fits together. This may not help as the thread is about a Norcold as I recall. That is a Norcold in my first photo. The second and third photos are a Dometic.
There is a burner tip at the bottom of a verticle tube where Keith is pointing with tape. The heat and exhaust hot gas go up a tube/pipe, the end of which is shown in the third photo. The hot exhaust leaves the tube, going up to the roof vent via a square plenum (not shown).
Keith explains that he sees at times the tube/pipe become almost plugged with rust and dirt and soot. When that happens the inlet air flow to the burner may be restricted because as exhaust flow is restricted. In that case the heat can even build higher than normal in the tube and scorch the wall behind the refrigerator or, I gather, disrupt the burner.
I hope this makes sense and helps visualize that part of the system. I am merely emphasizing what Davis just by chance showed me today. If it does not helping solve the problem described, maybe it is of interest to someone who has not seen the back of the refrigerators......as I had not.
OP, here closing out this thread. The frig now works as it should. I replaced the burner and orifice (kit) and the regulator. Not sure which was the culprit. One thing I did notice though: the burner had deteriorated quite a bit making the grill holes much larger than the new one. Anyhow, no more shhh-t-shhh-t-shhh.
jor