No Options Apply Gas burner assembly and flue vent problems

Boots in Action

Well-Known Member
Mar 13, 2017
2,054
1,806
113
Ferny Grove, Queensland
Here is another TRUE story from the fields of camping but this one is different - instead of helping someone else, it happened to ME!!
On the last couple of trips away, I noticed a black sooty mark on the fridge flue vents and on the side of the van whilst using gas for the fridge. At first I thought it must have been "dirty gas" if there is such a thing. The other alternative was incomplete combustion like having the choke stuck "on" on older cars - too much fuel and not enough air!! Lots of carbon and soot!!!
The whole thing came to a head after 4 days in a National park. The fridge was working well even in 30C temperatures and would regularly be down to 3C or 4C every morning. However on our last day, it struggled to get down to 8C and indeed started to go up through the day even with minimal opening and no added items inserted. The ice cream in the freezer was still okay but was starting to get soft and my beer was not as cold as before!! Something had to be done. Opened side vent and checked flame - seemed to be okay, steady and no yellow or flickering flame, but strange smell coming out to flue - indeed a light haze and the vent was blackened again with sooty black and greasy powder. Turned off gas and let burner assembly cool down and decided to try to clean outlet slots in gas burner assembly without removing same. Also checked air intake just near the gas jet opening. Managed to run a toothbrush across the slots in burner , but it appeared to be okay. Lit flame again but still no joy - temperature kept rising and late that evening condensation started to drip from evaporator in fridge section. Next morning gas still burning but temp up to 17C !! Disaster!! Packed up quickly and connected tug to van and switched to 12 volt operation when ready to depart. Two and a half hours later, arrived home very concerned. The only GOOD thing was that in the short time on 12 volts operation from tug, the condensation on evaporator had frozen, so at least the fridge still worked. But lots of black on vent and side of van. Only one thing to do - remove the fridge outside and see what's going on. Bu..er #@*%!!!.And a few other unprintable words!!
Now unlike a lots of the fridge installations some members have had, mine was excellent. No spare space at the sides (less than 1mm each side) and a really good well positioned baffle on the back wall of van directing all the air from below THROUGH the cooling fins at the back of fridge . Actually touching the cooling fins too!! I had fitted a deflector plate from the top of fridge to the top vent to direct the hot air out so it did not circulate around the space at the top, which I had also blocked off. Maybe I got a good one - a rare occurrence with Jayco and others it would seem!
A check of the gas burner assembly revealed a considerable amount of "debris" of some sort partially blocking most of the slots in the burner and some sort of corrosion was also closing the slots. Also, when I removed the flue vent for the fridge above the burner, found something that had been reduced to fine carbon nearly blocking the vent tube. Nothing solid but about the size of your thumb nail that had been vaporized by the heat. Insect/huntsman spider or similar maybe picked up at home when cold and did not get out in time before being fried??? First I have heard of such a thing!! That was where the debris on burner slots below came from I think. Gas jet was clean and not obstructed in any way. Cleaned out flue vent of blackened soot and greasy material. Also cleaned 240 volt and 12 volt heating elements. @Drover , the 12 volt wires to the heating element were very thick and well insulated unlike some others you have found on some of the vans you have worked on!!
Re-assembled and re-inserted back into space, but not before I was able to add some more reflective building material on all the fridge walls of the van including the top to improve insulation. No room for fiber glass as a very close fit. Also modified boiler stack to keep fan forced airflow (for cooling back of fridge) from affecting the heating.
Tested fully on 240 volts and achieved 2C on overnight test. Late next afternoon after being off for 12 hours, started on gas at ambient of 34C in the shade and achieved 3C in empty fridge compartment by morning . No more smell and no more black soot either. One important thing I did notice was the position of the flame indicator - that red indicator on green background . Lets you know when flame is burning and also measures the amount of electricity generated at the thermo couple which is heated by the gas flame. I did give the thermo couple a bit of a clean and the indicator now goes three quarters of the way over on the scale, when before it only managed to go about a third of the way. This to me indicated a hotter flame on the thermo couple than before and is something I will watch for in the future A low reading would seem to indicate a low heat flame?
If anyone has had a similar occurrence or is having trouble with your 3 way fridge not performing too well on gas, perhaps this saga will be of interest to you. Better to learn from someone else, before it happens to you.
 

Boots in Action

Well-Known Member
Mar 13, 2017
2,054
1,806
113
Ferny Grove, Queensland
Here is another TRUE story from the fields of camping but this one is different - instead of helping someone else, it happened to ME!!
On the last couple of trips away, I noticed a black sooty mark on the fridge flue vents and on the side of the van whilst using gas for the fridge. At first I thought it must have been "dirty gas" if there is such a thing. The other alternative was incomplete combustion like having the choke stuck "on" on older cars - too much fuel and not enough air!! Lots of carbon and soot!!!
The whole thing came to a head after 4 days in a National park. The fridge was working well even in 30C temperatures and would regularly be down to 3C or 4C every morning. However on our last day, it struggled to get down to 8C and indeed started to go up through the day even with minimal opening and no added items inserted. The ice cream in the freezer was still okay but was starting to get soft and my beer was not as cold as before!! Something had to be done. Opened side vent and checked flame - seemed to be okay, steady and no yellow or flickering flame, but strange smell coming out to flue - indeed a light haze and the vent was blackened again with sooty black and greasy powder. Turned off gas and let burner assembly cool down and decided to try to clean outlet slots in gas burner assembly without removing same. Also checked air intake just near the gas jet opening. Managed to run a toothbrush across the slots in burner , but it appeared to be okay. Lit flame again but still no joy - temperature kept rising and late that evening condensation started to drip from evaporator in fridge section. Next morning gas still burning but temp up to 17C !! Disaster!! Packed up quickly and connected tug to van and switched to 12 volt operation when ready to depart. Two and a half hours later, arrived home very concerned. The only GOOD thing was that in the short time on 12 volts operation from tug, the condensation on evaporator had frozen, so at least the fridge still worked. But lots of black on vent and side of van. Only one thing to do - remove the fridge outside and see what's going on. Bu..er #@*%!!!.And a few other unprintable words!!
Now unlike a lots of the fridge installations some members have had, mine was excellent. No spare space at the sides (less than 1mm each side) and a really good well positioned baffle on the back wall of van directing all the air from below THROUGH the cooling fins at the back of fridge . Actually touching the cooling fins too!! I had fitted a deflector plate from the top of fridge to the top vent to direct the hot air out so it did not circulate around the space at the top, which I had also blocked off. Maybe I got a good one - a rare occurrence with Jayco and others it would seem!
A check of the gas burner assembly revealed a considerable amount of "debris" of some sort partially blocking most of the slots in the burner and some sort of corrosion was also closing the slots. Also, when I removed the flue vent for the fridge above the burner, found something that had been reduced to fine carbon nearly blocking the vent tube. Nothing solid but about the size of your thumb nail that had been vaporized by the heat. Insect/huntsman spider or similar maybe picked up at home when cold and did not get out in time before being fried??? First I have heard of such a thing!! That was where the debris on burner slots below came from I think. Gas jet was clean and not obstructed in any way. Cleaned out flue vent of blackened soot and greasy material. Also cleaned 240 volt and 12 volt heating elements. @Drover , the 12 volt wires to the heating element were very thick and well insulated unlike some others you have found on some of the vans you have worked on!!
Re-assembled and re-inserted back into space, but not before I was able to add some more reflective building material on all the fridge walls of the van including the top to improve insulation. No room for fiber glass as a very close fit. Also modified boiler stack to keep fan forced airflow (for cooling back of fridge) from affecting the heating.
Tested fully on 240 volts and achieved 2C on overnight test. Late next afternoon after being off for 12 hours, started on gas at ambient of 34C in the shade and achieved 3C in empty fridge compartment by morning . No more smell and no more black soot either. One important thing I did notice was the position of the flame indicator - that red indicator on green background . Lets you know when flame is burning and also measures the amount of electricity generated at the thermo couple which is heated by the gas flame. I did give the thermo couple a bit of a clean and the indicator now goes three quarters of the way over on the scale, when before it only managed to go about a third of the way. This to me indicated a hotter flame on the thermo couple than before and is something I will watch for in the future A low reading would seem to indicate a low heat flame?
If anyone has had a similar occurrence or is having trouble with your 3 way fridge not performing too well on gas, perhaps this saga will be of interest to you. Better to learn from someone else, before it happens to you.

Hello there @mikerezny, @1DayIll, @DRW and @Drover :
A follow up on the above problem for information of those interested. Have just returned from 7 days off grid with minimum temps at night of 19 to 20C and daytime temps of between 26 and 32C. No problems with fridge keeping temps below 6C during the day (including my beer and milk, butter etc. ) and keeping food such as icecream, frozen meat, sausages and chicken tenders and ice for our Jim Beam afternoon drinkies in the freezer section. At night time at lower temps and less opening of fridge door, fridge temps regularly dropped to 2 or 3C. And no "bl....y" sooty discharge from flue. Problem sorted thank goodness and a suitable test too!!