This problem has been driving me crackers.
I have a Dometic RM4230 fridge in my 2007 Triton. It only has 3 temperature settings. The lowest setting does absolutely nothing. The middle setting is not quite enough to get the fridge down to 5C, even at night. The highest setting is simply too hot. The fridge gets down to 5C OK but there is a massive amount of heat coming off the cooling fins and the stove above the fridge gets noticeably warm, plus it seems to use a lot of gas. (Propane)

Incidentally, the fridge works fine on 230 Vac so it's not a blockage or lack of refrigerant.

I've had the fridge out a couple of times now and cleaned the jet and the flue, it all looks virtually brand new, the previous owner from new didn't use gas for the fridge. I have even taken the control valve apart and checked the 3 tiny pilot holes, all clean.

The fridge is set up in my garage, temporarily connected to a butane gas bottle and the temperature seems to be coming down steadily after 3 hours.

I started to think about the gas regulator in the gas locker, wondered if it was faulty when I discovered that it is factory set at 30 mbar. Now my portable clip on regulators are 29mb for butane and 37mb for propane.

The recommended input for the gas fridge is 29 for butane and 37 for propane. So, is my poor performance down to the relatively low pressure of the fixed propane regulator at 30mbar ?

When the fridge in the garage has stopped cooling down on butane, I shall swap over to a propane cylinder with a 36mbar clip on regulator and see if there is a difference.

Anybody else experienced something similar or have I missed out on some other fault in the fridge?

once read to solve some issues turn the fridge upside down while switched off then try cooling again, when back up right way, I don't know why or if it works
is the door seal sealing and no gaps letting warm air in?
have you tried filling the frozen cupboard thing with frozen peas to help cool the system
suppose the gas side has a thermostat is that at fault?
is the fridge level? there is something about 10 degrees angle stopping fridges working
is the chimney clear?
really hoping you have a co alarm in garage if working gas fridge, be safe, have good air flow
apology for ramblings

Hi Aaron, I have already ordered the parts to build your extraction system, excellent article, thank you.

Pop540, I have checked all the things that you have mentioned and ruled them all out, but thank for the input.

My main point being that on the middle heat setting, the fridge goes down to 5C on butane at 29mb. I am currently observing the temperature using propane on the same setting using a 37mbar regulator. I'll report back when I have some info. Only turned the fridge on about an hour ago.

Quote: Ray Lawrence wrote in post #1

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I started to think about the gas regulator in the gas locker, wondered if it was faulty when I discovered that it is factory set at 30 mbar. Now my portable clip on regulators are 29mb for butane and 37mb for propane.

The recommended input for the gas fridge is 29 for butane and 37 for propane. So, is my poor performance down to the relatively low pressure of the fixed propane regulator at 30mbar ?

When the fridge in the garage has stopped cooling down on butane, I shall swap over to a propane cylinder with a 36mbar clip on regulator and see if there is a difference.

Anybody else experienced something similar or have I missed out on some other fault in the fridge?

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Zitat

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The Regulator
A suitably rated regulator must be included in the connection between the cylinder and the appliance.The regulator is precisely set to control the pressure of the supply and Must Not Be Adjusted. Replace any regulator, which is not working properly, or after 10 years’ of life.
Regulators must be marked BS3016 or BSEN12864 For Caravan Holiday Homes and Residential Park Homes the regulator must have an
outlet pressure of 28 mbar for Butane and 37 mbar for Propane and be marked BS3016 or BS EN 12864 (for cylinder use) or BS EN 13785 when connected to a piped supply. Where an Automatic Change Over Device or Regulator is fitted to multiple Propane cylinder installations, this must have an outlet pressure of 37 mbar and be marked BS EN 13786.
For Touring Caravans and Motor Homes, in 2003 BS EN 1949 was introduced which requires the appliances be supplied at 30 mbar
for either Butane or Propane. This regulator must be marked BS12864 Annex D. Where an Automatic Change Over Device or Regulator
is fitted to this must be marked BS EN 13786 Annex D.Touring Caravans and Motor Homes, produced before 2003 require an outlet pressure of 28 mbar for Butane and 37 mbar for Propane and must be marked BS3016 or BS EN 12864.
Guidance will be given in the manual for your caravan and a label attached to the gas inlet in the gas locker.

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See attachment below

Hob, thank you for the clarification on the regulator regulations.
I am not about to tamper with the factory installed regulator but I have a keenly enquiring mind and wondered why my fridge is less efficient on propane than butane. Once I have established the reason, I can relax knowing there is nothing more that I can do...........other than revert to butane as my caravan gas supply.

I reiterate that my fridge works perfectly on 230Vac and therefore there is nothing wrong with the refrigerant, level etc, just the gas heat source.

As I suspected, the fridge went down to 5C on propane at 37mbar.

So, the 30mbar regulation for caravans after 2003 has an impact on the gas appliance efficiencies.

Why can't you have two regulators? I suppose it's to stop somebody contriving to connect a butane cylinder to a 37mbar regulator with very hot consequences

Anyway, now I know it's not my fault or anything I can fix........pass another warm beer please

Does that mean that the tiny gas flame running the fridge is 12% cooler on propane?
If so it should still get cold but take longer shouldn't it?
TonyP

Hi Frantone,
in my experience, there comes a time when the heat input from the flame matches the cooling loss through the walls of the fridge and it never catches up. For example, in my caravan on the middle setting, the temperature would get down to 10 or 11C and not go any lower.

Pepe, I agree with your summation of using butane as I seldom go camping in the cold.
I bought a fresh bottle of propane yesterday and the salesman agreed that I could exchange a 6 kg propane cylinder for a 7 kg butane.

Aaron, thanks to you and John England, I have built and installed a two fan extractor system.

I would never have been able to work out how to reverse the polarity of the relay and I spent a long time messing about with the c/o contacts trying to get it to work without the very fiddly modification to the pcb. Succumbed in the end and it works perfectly :)

I am not able to test the efficiency here in the sunny UK, it's just about 20C in my back garden. However, I do have a couple of points to raise.
I'm unsure if two fans are needed. After running them for a couple of minutes, only the fan closest to the flue continues to discharge warm air, the other is at ambient.
Talking of ambient, I'm unsure how this system will work in a hot awning? Assuming it gets to 35C in the awning. The fans kick in and draw the hot air off the cooling fins of the fridge. However, they will still be drawing air in the bottom at 35C so I'm guessing that all the fans are doing is recirculating the warm air. I have no experience of this yet and am just thinking around the project, perhaps Aaron, you can enlighten me with your experience.

What would definitely work would be some kind of ducting from the lower grill to the ground, preferably out through the draught skirt and under the caravan........hmmmm

if it gets that hot in an awning you will most likely have some panels out or just be using a sunshade.

Being a UK camper with our very variable weather, we often go out in the morning in the pouring rain and cold. Subsequently the sun comes out and we come back to a baking hot awning and struggling fridge. That's the main reason for the automatic fans.