My van gas source is 2x8.5kg bottles fitted with safety valves. (Picture shown).
I know there have been many opinions expressed here regarding these valves. I for one am very happy with these valves.
What I have found with these valves, however, is that there is a slight reduction in gas pressure after fitting these valves.
I was not aware of this until I read posts on other blogs and it dawned on me that perhaps this may be a problem that I, as perhaps others, may also be experiencing.
I can only speak of my van's fitted appliances and not those of others, but the solution worked well for me.
My appliances: Thetford/Spinflo MK3 stove/oven. Dometic RM4605 Fridge. Truma E2400 Gas heater. Girard GSWH-1M Instant H/W.
Problems experienced: Fridge...no visible problem experienced. Stove/Oven...yellow tips on burner flames. Gas heater...several attempts required to ignite and run heater. Instant H/W...varying water temps.
OK, so when trouble shooting the appliances the manuals quite often refer to incorrect gas pressure as a possible fault.
Several posts I read had similar problems and they were overcome by adjusting the gas pressure.
Now, I have a disclaimer here and am not suggesting anyone to fiddle with their gas systems. What I am saying is that this worked for me.
The suggestions that I read related to the adjustment of the gas pressure valve. To remove the black cover, access the adjusting knob with a spade screw-driver and in steps to adjust the pressure.
Turn right to increase pressure, turn left to decrease pressure. Turn in one quarter steps and check improvement or not.
One quarter turns are very slight adjustments and the recommended adjustments were from half to full turns.
So I started with the stove burners, turned them on and they burned with the usual yellow tips. Adjusted the gas pressure quarter turn and result was less yellow tips, adjusted the gas pressure to half turn and the flame was a pure blue flame.
Then turned on the gas heater which ignited and remained burning without flaming out as previously.
Then turned on Instant H/W at high setting and water ran consistently constantly hot. Tried a warm setting with the same result. Previously the temperature would pulse off and on.
I have yet to monitor what improvement, if any, is with the fridge.
I am not sure of the legal consequences of adjusting lpg gas pressures. That is not the purpose of this post.
But if you feel that you may be having gas appliance operational problems then perhaps a diplomatic suggestion to your gas technician to check pressures may be worthwhile.
Going by other blog sites, owners have used this option after the experts have investigated and concluded that no faults exists.
On our previous caravan we had a manual start 3 way gas frig, always needed several attemps to start it on gas and then one day I had a Gas Certified man call into home to do some work on the gas line.
He told me to go fishing with the "gas safety fuse" it will cause other issues, so I took it off and the frig actually started after a couple of flicks every time from then on.
Another statement he made was " most gas leaks are smaller then the amount of gas your appliance is using. Worn pigtail which I have at the moment on my second bottle, the leak is so minuscule that I had doubts about it leaking. The gas safety fuse would not pick it up.
This caravan would sit for weeks withou being used, I just put it down to not being used.
I recently had the experience of the fridge not starting on gas when we pulled up at a stay. The gas hot water was heating and the gas stove was working so we turned off the hot water and the fridge started. We then turned on the hot water heater and all was well. This seems like a similar problem to the OP's.